Office 365 email access requires Outlook for Mac 2016 or newer.
Launch your Microsoft Office for Mac Outlook client by navigating to:
Check the box next to “Make Outlook the default application for email, calendar, and contacts” then click Add Account.
Click on Exchange Account.
Enter your primary email address in the “E-mail address” field. Enter your username and password. Make sure “Configure automatically” is checked, then click Add Account.
Check the “Always use my response for this server” option and click the Allow button.