Viewing Your License
To get an overview of your own, personal license, you can log in simply with your license key and email address - no full-fledged account and therefore no password is required.
You can access this view through either of the following ways:
(a) Visit https://account.git-tower.com/license_user or...
(b) In the Tower app, select "Registration..." (from the main "Tower" menu on macOS, or from the "File" menu on Windows). Then, click "Manage Your License" in the dialog.
You can then log in using your license key and email address.
This page contains some helpful information:
License Information: You can see your license key and - if you're working in a team - who's managing your licenses.
Activations: Any Tower license may only be used by one user. However, it's totally fine for a user to install a license on more than one of her devices. You find a list of all devices where Tower has been activated - and can deactivate unused ones.