Outlook on Windows

In the Ribbon, look for the "Junk" menu

If you have enabled Simplified Ribbon (with smaller icons and fewer descriptions), look for the "Junk" menu here

Select "Junk E-mail Options..."

Select the "Safe Senders" tab

Select "Add..."

Enter an email address you wish to be on your Safe Senders List

Select "OK"

Before closing "Junk Email Options," select "Apply" to save your changes

Outlook Online

Open Settings by selecting the gear icon on the top-right corner of the screen

Select "Mail" → "Junk email"

Scroll to "Safe senders and domains" and select "Add"

Enter an email address you wish to be on your Safe Senders List

Press "Enter" on your keyboard

Select "Save" for the changes to take effect