To sign in to Outlook on the web using your work or school account in Office 365:
Enter the email address and password for your account.
Select Sign in.
Note: To sign in to Office 365 using another account, select Use another account the next time you sign in.
If you're signing in to Office 365 operated by 21Vianet (in China):
If you're trying to sign in with an Outlook.com, Hotmail, Live, or MSN email account, see How to sign in to or out of Outlook.com.
Problems signing in or out?
To sign out of Outlook on the web:
Select your account picture at the top of the screen.
If you don't see your picture at the top of screen, check to see if ad blocking is turned on. Sometimes this prevents the picture from showing.
Select Sign out.
To prevent Outlook on the web from signing you in to your work or school account automatically, clear the Keep me signed in check box the next time you sign in to Office 365.