To setup outgoing email using Office 365 navigate to Settings > My Details > Setup Incoming and Outgoing Email > Office 365, then click Sign in with Microsoft and add the email address and password you want to send emails from.

This email address doesn't have to be the same one you use to login, and more than one staff user can send emails using the same email address.

Once Microsoft have verified your login details a pop up will appear in AccountancyManager to prompt you to automatically set up an email forwarding rule. This rule will forward a copy of every email you receive to your account.