Step 1: Open Outlook 2016 for Mac
Open Outlook from withing your Applications folder.
Step 2: Select Preferences in the Outlook menu
In the top left of your screen select Outlook and then select Preferences... from the menu.
Step 3: Select Signatures
Select Signatures from the Outlook Preferences menu.
Step 4: Add Your Signature
Click into the Signature box and begin typing your signature.
Right-click (or control-click) in the signature box and select Font... to change font, color, and size.
Click Format in the top menu and select Insert Picture to add a picture or logo.
Set Default Signature
Under Choose default signature, make sure your signature is selected under New Messages and Replies/Forwards.
Step 8: Close Window to Save
To save just close the window. Outlook will automatically save the signature.