The primary click on the Magic Mouse can be changed to left or right to accommodate left handed users.

Change the Primary Click on the Magic Mouse

1. Go to your Launchpad, click on “System Preferences”, and open “Mouse”

2. Under “Secondary click”, change the option to your desire preference

Note: If you are using a non-Magic Mouse, your Mouse settings will look like this. Change the “Primary mouse button” option to your desired preference.