The license is purchased for each device separately?

No. The license is purchased for the necessary number of users: 1, 2, 3 and more.

One specific user has the right to use LeaderTask on any number of devices (Windows, Mac, Android, iPhone, iPad).

As the user ID serves the email. The identifier is an analog of the passport number.

To use LeaderTask at the same time on several devices, it is necessary to come on each device into the program, using the same couple of email-password.