Most people use email every day without thinking too much about what sits behind it. You open Outlook, send a message, reply to a customer, check a calendar invite and move on with your day.

Then someone asks a perfectly reasonable question.

“Should this be a shared mailbox?”

Or: “Can we just give everyone access to Sarah’s old inbox?”

Or: “Why does the meeting room have an email address?”

That is where things can get a little muddled.

In Microsoft 365, not every email address is designed to work in the same way. A personal mailbox, a shared mailbox, a distribution list and a room mailbox may all look like “email addresses” on the surface, but they do different jobs.

Choosing the right one makes life easier. It helps your team find the right messages, manage access properly, avoid password sharing and keep business communication tidy as people join, leave or move roles.

Quick reference guide

Type	Best used for	Who accesses it?	Example
User mailbox	An individual person’s email	One named user	jack@company.co.uk
Shared mailbox	A team-managed email address	Multiple permitted users	info@company.co.uk
Microsoft 365 Group	Wider team or project collaboration	Group members	Project team
Room mailbox	Booking a physical room	Staff booking meetings	Boardroom
Equipment mailbox	Booking shared equipment	Staff booking resources	Projector
Distribution list	Sending one email to several people	List members receive the message	allstaff@company.co.uk
Archive mailbox	Storing older email	Usually linked to a user mailbox	User archive
Former employee mailbox	Managing email after someone leaves	Depends on business need	Old staff mailbox

Still unsure? Here's a little more explanation for each:

User mailboxes

A user mailbox is the standard mailbox most people have.

This is the mailbox connected to an individual person’s Microsoft 365 account, such as:

• jack@company.co.uk
• jill@company.co.uk

It is where that person receives their own email, manages their calendar and keeps their contacts. In most cases, it is linked to their Microsoft 365 licence and login.

User mailboxes are best for personal work communication. They are not usually the right choice for team addresses such as info@, accounts@ or support@, because those addresses often need to be accessed by more than one person.

A common mistake is allowing several people to use one person’s login so they can all see the same mailbox. That may feel convenient in the moment, but it creates problems. You lose accountability, it becomes harder to manage access, and it can create security risks if a password is shared around.

If several people need to manage the same stream of emails, a shared mailbox is usually a better fit.

Shared mailboxes

A shared mailbox is designed for an email address that more than one person needs to access.

Typical examples include:

• info@company.co.uk
• accounts@company.co.uk
• support@company.co.uk
• reception@company.co.uk
• enquiries@company.co.uk

Instead of logging in with a shared password, each authorised user signs in with their own Microsoft 365 account. They are then given permission to open and use the shared mailbox.

Access can be added or removed properly when someone joins the team, changes role or leaves the business. It also avoids the messy habit of sharing passwords, which is never a good idea.

A shared mailbox is useful when a team needs to:

• Monitor incoming emails together
• Reply from a shared address
• Keep visibility of customer or supplier conversations
• Cover holidays, sickness or staff changes
• Stop important emails being stuck in one person’s personal inbox

For example, if three people help manage supplier invoices, using accounts@ as a shared mailbox makes much more sense than sending everything to one person. Everyone who needs access can see the same inbox, and replies can come from the accounts@ address rather than from an individual user.

Shared mailboxes are often available without a separate licence, but there are limits and exceptions. Storage, archiving, compliance requirements and the way the mailbox is used can all affect what is needed. It is always worth checking before assuming.

Microsoft 365 Groups

A Microsoft 365 Group is a little different. It is not just a mailbox.

A group can give a team access to a shared inbox, but it can also connect to other Microsoft 365 tools, such as a shared calendar, SharePoint files, Planner and Teams.

That makes Microsoft 365 Groups useful for teams, projects or departments that need more than email.

For example, a project team may need:

• A shared place for conversations
• A shared calendar
• A shared file area
• A task plan
• A connected Microsoft Teams workspace

In that case, a Microsoft 365 Group may be more suitable than a simple shared mailbox.

The easiest way to think about it is this:

Use a shared mailbox when the main job is managing emails sent to one shared address.

Use a Microsoft 365 Group when the team needs a wider collaboration space, not just an inbox.

For many businesses, both have their place. The trick is choosing the one that matches the way people actually need to work.

Room mailboxes

A room mailbox represents a physical room that people can book through Outlook.

Examples might include:

• Boardroom
• Meeting Room 1
• Training Room
• Consultation Room
• Interview Room

The room has its own calendar. When someone creates a meeting in Outlook, they can invite the room in the same way they would invite a person. Depending on how it has been configured, the room can accept or decline the booking based on availability.

This helps avoid double bookings and removes the need for spreadsheets, paper diaries or the classic “who has booked the boardroom?” conversation.

Room mailboxes are especially helpful when rooms are shared across different teams, departments or locations. They also make it easier for staff to check availability themselves rather than relying on one person to manage bookings manually.

Equipment mailboxes

An equipment mailbox works in a similar way to a room mailbox, but it is used for bookable items rather than physical rooms.

Examples might include:

• Projectors
• Company vehicles
• Recording equipment
• Specialist devices
• Loan equipment

The equipment gets its own calendar, so staff can book it when they need it. Others can then see whether it is available.

This can be useful for any organisation where shared equipment is regularly used by different people. It reduces confusion, helps avoid double bookings and makes it clearer who has reserved what.

It works best when there are clear rules around how equipment should be booked, collected, returned and looked after. The mailbox can help with the booking process, but it should sit alongside sensible internal procedures.

Distribution lists

A distribution list is not really a mailbox, but it is often confused with one.

A distribution list is used to send one email to several people at once.

Common examples include:

• allstaff@company.co.uk
• managers@company.co.uk
• finance-team@company.co.uk

When someone sends a message to the distribution list, the message is delivered to the people who are members of that list.

This is useful for announcements or team-wide updates. For example, HR might use allstaff@ to send a company notice, or a department head might use managers@ to update several people at once.

The important thing to remember is that a distribution list does not usually give you a shared inbox. It sends messages out to a group of people.

So, if the aim is to send one message to many people, a distribution list may be right.

If the aim is for several people to manage one inbox together, a shared mailbox is usually the better option.

Archive mailboxes

An archive mailbox is used to store older email while keeping it accessible.

It is usually connected to a user’s mailbox and can form part of a wider approach to retention, storage management or compliance.

For example, instead of letting a user’s main mailbox become overloaded with years of old messages, older items may be moved into an archive mailbox. The user can still access the archive, but their primary mailbox stays easier to manage.

Archiving needs careful thought. It is not the same as exporting emails to a file and forgetting about them. Depending on your organisation, you may need to consider how long information should be kept, who should have access to it, and whether any legal, regulatory or contractual requirements apply.

This is an area where it is sensible to ask for advice before making changes, especially if email records are important to your business operations.

Former employee mailboxes

Leaver mailboxes are one of the most common areas where businesses get stuck.

Someone leaves the organisation, but their mailbox still contains useful information. Customers may still be emailing them. Colleagues may need access to old conversations. The business may need to keep certain records.

The wrong approach is to leave the old account active and let other people keep signing into it. That creates security issues and makes it harder to manage access properly.

Depending on the situation, there are several better options. The mailbox may be converted to a shared mailbox, access may be delegated temporarily, forwarding or an automatic reply may be set up, or the data may need to be preserved in line with retention requirements.

The right answer depends on what the business needs.

For example, if customers are still emailing a former employee, you may need an automatic reply telling them who to contact instead. If a manager needs to check historic messages, delegated access may be more appropriate. If the mailbox needs to be retained for compliance or business continuity reasons, it should be handled carefully before the user account is removed.

Before deleting or reusing anything, it is worth checking. A few minutes of planning can prevent a lot of awkward email recovery work later.

Which one should you use?

Here is the simple version.

Need an email address several people can manage? Use a shared mailbox.

Need to email lots of people at once? Use a distribution list.

Need a shared workspace with files, conversations, tasks and a calendar? Consider a Microsoft 365 Group.

Need to book a meeting room? Use a room mailbox.

Need to book a shared item, such as a projector or other piece of equipment? Use an equipment mailbox.

Need to keep older email accessible? Look at archive mailbox options.

Need to handle a leaver’s mailbox? Ask before deleting, forwarding or giving access.

Most mailbox issues come from using the wrong tool for the job. A shared mailbox can be brilliant for a team inbox, but it is not the same thing as a distribution list. A room mailbox can make bookings much easier, but only if it is configured properly. A former employee’s mailbox may need careful handling rather than a quick workaround.

When to ask for help

You do not need to know every Microsoft 365 admin setting to make good decisions about mailboxes. You just need to know when something should be set up properly.

It is worth asking for help if you are:

• Setting up a new shared mailbox
• Giving people access to sensitive inboxes
• Removing access when someone changes role
• Handling a mailbox after someone leaves
• Tidying up confusing or duplicate email addresses
• Reviewing who can access accounts@, info@ or other shared addresses
• Managing mailbox storage or archiving
• Trying to reduce password sharing
• Unsure whether you need a shared mailbox, group or distribution list

At PS Tech, we help businesses get more from Microsoft 365 by making sure it works properly for the way their teams actually operate. That includes setup, support, security, backup and practical advice around everyday tools like Outlook, Teams and SharePoint.

Email might feel simple on the surface, but the way mailboxes are structured has a real impact on security, productivity and business continuity. Get the basics right, and your team spends less time hunting for messages, chasing access or untangling avoidable problems.