Select Manually configure server settings or Additional server types
click Next.
Select IMAP.
Fill in the following fields:
Your name and the e-mail address you want to add
Account Type: select IMAP in the drop-down menu
Incoming mail server: outlook.office365.com
Outgoing mail server: smtp.office365.com
User Name: enter the e-mail address again
Password: the password for your e-mail address
Click More Settings go to
outgoing server, make sure the "outgoing server is authenticating" is checked (first line)
go to the Advanced tab.
Enter the port numbers and select the encrypted connections.
Incoming mail server: 993
Type of encrypted connection: SSL
Outgoing mail server: 587
Type of encrypted connection: TLS
Click OK > OK > Next > Finish.