Outlook on the web (OWA): complete guide to Microsoft 365 webmail

Outlook on the web (still widely called OWA, short for Outlook Web App) is Microsoft 365 webmail. It gives you your email, calendar, contacts and shared mailboxes in any browser, with nothing to install. This guide covers signing in, everyday email and calendar tasks, the settings people look for most, keyboard shortcuts and fixes for common problems.

• Applies to: Microsoft 365 Business Basic, Standard and Premium
• Time: 2 minutes to sign in; dip into the sections you need
• Difficulty: Beginner

Sign in to Outlook on the web

1. Go to outlook.office.com in Edge, Chrome, Firefox or Safari. (outlook.cloud.microsoft is Microsoft's newer address for the same thing, and office.com → Outlook works too.)
2. Enter your full work email address, such as you@yourbusiness.co.uk, and select Next.
3. Enter your password and approve the multi-factor authentication (MFA) prompt in Microsoft Authenticator, or type the code sent to your phone.
4. Stay signed in? Choose Yes only on your own device. On a shared or public computer, choose No and sign out when you've finished (profile picture, top right → Sign out).

Find your way around

• Left-hand app bar: icons for Mail, Calendar, People, and further apps such as To Do, OneDrive and Teams.
• Folder pane: your Inbox, Sent Items and other folders, then any shared mailboxes and groups underneath.
• Message list and reading pane: select a message to read it on the right.
• Search box along the top, and Settings (the gear icon) at the top right. Every setting can be found by typing its name in the search box at the top of the Settings window. That's the quickest way to find anything below.

Everyday email tasks

Write and send a message

1. Select New mail (top left), or press N.
2. Type names in To. Colleagues appear from your organisation's address book as you type. Use Cc for people who should be kept informed and Bcc to hide recipients from each other.
3. Add a subject and message, then select Send (or press Ctrl+Enter).

• Send later: select the arrow next to Send → Schedule send, then pick a time. Outlook sends it even if your computer is off.
• Undo send: turn on a delay of up to 10 seconds under Settings → Mail → Compose and reply → Undo send. An Undo button then appears briefly after you send.
• Send from a shared address: while writing, open Options → Show From, then choose the address in the new From box. You need Send As permission (see Give someone access to your mailbox).

Attachments and large files

Select Attach (paperclip) or drag files into the message. For anything large, choose a file from OneDrive and send it as a sharing link instead of a copy. The recipient always gets the latest version and you avoid size limits.

By default Microsoft 365 limits messages to about 35 MB including attachments, and Outlook on the web leaves headroom for encoding, so in practice keep attachments under about 25 MB. Your administrator can raise the limit, but many recipients' mail servers won't accept anything much bigger.

Keep your inbox under control

• Focused Inbox splits mail into Focused and Other tabs. Turn it on or off under Settings → Mail → Layout. If an expected email "hasn't arrived", check the Other tab first.
• Sweep removes all mail from one sender in a single step, and can keep doing it automatically.
• Pin or Flag messages you need to come back to, and Archive (E) to file read mail out of the inbox.
• Rules move, forward or flag mail automatically. See Create inbox rules.

Search

Type in the search box at the top. Use the filter icon at the end of the box to narrow by folder, sender, date range or "has attachments". Search covers your whole mailbox, including the Online Archive if you have one.

Report junk and phishing

Select a suspicious message, then Report → Report phishing or Report junk. This moves it out of your inbox and helps Microsoft's filters. If you clicked a link or entered your password, change your password straight away and tell your administrator.

Shared mailboxes and other people's mailboxes

Once an administrator has given you access (see Create a shared mailbox), there are two ways to use it:

• In your folder pane: right-click Folders (or your own mailbox name) → Add shared folder or mailbox, type the shared address and select Add. It appears below your own folders. Mail you send from here is saved in your own Sent Items unless your administrator changes that.
• In its own tab: select your profile picture (top right) → Open another mailbox, then type the address. This opens the full mailbox with its own settings, such as its automatic replies and signature.

Calendar

• Create an event: select Calendar in the app bar, then New event, or click a time slot. Switch views with Day, Work week, Week and Month.
• Invite people: add them in Invite attendees. Turn on Teams meeting to add a join link automatically.
• Find a time that suits everyone: open Scheduling Assistant to see colleagues' free and busy time side by side.
• Share your calendar or open someone else's: select Share on the toolbar, or Add calendar → Add from directory to open a colleague's. Full details, including sharing with people outside your business, are in Share your calendar.
• Working hours and time zone: set under Settings → Calendar and Settings → General → Language and time. A wrong time zone makes meetings appear at the wrong time for everyone you invite.

Contacts (People)

Select People in the app bar. New contact adds a personal contact. Your organisation's directory (everyone in your Microsoft 365 tenant, plus groups and shared mailboxes) is listed separately and is maintained by your administrator. You can also create a contact list for people you email together often.

Where to find common settings

Select Settings (gear icon), then use the search box at the top of the Settings window if a heading has moved. Microsoft reorganises these menus from time to time.

Keyboard shortcuts

These work with the default Outlook shortcut style. Press ? in Outlook on the web to see the full list.

Troubleshooting

Outlook on the web won't load, or shows a blank page or error

Open a private (InPrivate or Incognito) window and sign in there. If that works, clear cookies for office.com, outlook.office.com and microsoftonline.com in your normal browser, and turn off ad-blocking or privacy extensions for those sites. Check Microsoft's service status page for outages. Administrators can also see detailed service health in the admin centre.

"We couldn't find an account with that username" or the password is rejected

Make sure you're typing the full address and that it's your Microsoft 365 address (not a personal Outlook.com account). If you've forgotten the password, use Forgot my password if your organisation has turned it on (see Let users reset their own passwords), or ask your administrator to reset it.

An email shows in Outlook on my PC but not in the browser (or the other way round)

Outlook on the web always shows what's actually in Microsoft 365. If a message is missing here, check the Other tab, Junk Email, and any rules that move mail. If a message is here but not in classic Outlook, Outlook on the PC hasn't finished syncing. See Repair Outlook.

I can't open or attach a file

Check the file is under about 25 MB, or share it from OneDrive instead. Some file types (such as .exe and other programs) are blocked for security. If a document won't preview in the browser, download it and open it in the desktop app.

It keeps signing me out

Choose Yes at Stay signed in? on your own device, and make sure your browser isn't set to delete cookies when it closes. Your administrator may also have set a session time-out for security.

Last reviewed: October 2026