Before you start configure the mailbox, make sure there is not same mailbox already configured on your mobile. If so, please remove this mailbox from your device.
Open the Gmail app.
Tap the menu icon in the upper left corner > Settings > Add account > Exchange and Office 365.
Important: Do NOT choose "Outlook, Hotmail, and Live" unless you want to sync email only and not calendar/contacts.
Enter your full email address and tap Next.
Enter your password and tap Next.
you may see a Redirect request screen. Tap OK.
On the Incoming server settings screen, change your server to outlook.office365.com.
Follow any prompts you may get for security or device permissions, sync settings, and more.
You may also be asked to confirm Remote security administration and approve additional security measures. In this case, choose OK or Activate.
Go to the inbox you just set up. If you see an email that says "Action Required to Sync Email," open it and tap Use another Mail app instead.
If you don't see this message and emails are syncing, skip this step.
Pull down the Android notification bar by swiping down from the top of your screen.
If you see a notification that reads "Unable to sync calendar and contacts," tap it. Then tap Allow to give access and you're done!
Note: If you don't see a sync error, verify your calendar and contacts are syncing.