How to Add a Second Outlook Account (macOS)
Office 365: Adding a second (resource/service) account to your Outlook for Mac client
- Open Outlook for Mac then go to the File menu to Preferences.
- Select Accounts from the Preferences options then click on the + icon at the bottom left and choose New Account...
- Enter the resource/service account's email address.
- Enter the resource/service account's password.
- That should do it! You should now see a second account (below your own Exchange account) in Outlook for Mac.