Outlook
To follow the steps below, make sure your ribbon view in Outlook is set to Classic Ribbon. You can select this by opening the drop down from the small down arrow on the right hand side of your Outlook screen.

Once you can see the full ribbon, you will select the Junk mail drop down from the Home Tab

Select Junk E-Mail Options…
From the pop up, select the Safe Senders tab
Click the Add… button

Type the email address of who you would like to be added to your Safe Sender list, then hit ok

Once added, make sure to hit Apply to save and you are done!