where to enter the lic key on a mac

Hi, basic question i know but i need to tell a user where they need to enter their licence key on their mac airbook
Being windows through and through, and never having touched a mac in my life i can’t tell the guy where the key gerts entered.

Regards…

The mac version doesn’t use a license key it uses a License file (file with .dat extension). You enter it by chosing change license from the avast menu.
The mac version is not free you can purchase a license on the avast website.