To get theme auto-updates and unlock all the available theme features, you have to register your theme purchase code. To do that, please open Theme Options -> Product Activation and enter your Envato purchase code. If you don’t know where to find it, please read this article https://help.market.envato.com/hc/en-us/articles/202822600-Where-Can-I-Find-my-Purchase-Code-
During the registration, the system will set up your personal GT3 account on https://gt3accounts.com/app/ automatically where you will be able to manage all your purchase codes and get dedicated support. You will receive an email with your account credentials when your account is ready. Feel free to update the password at any time.
Important: To register the theme purchase code you must have the parent theme active (not a child one).