How to activate my Setapp subscription on iOS?
Click on the Setapp symbol in the menu bar, then "Open Setapp". Search and select "NotePlan". Right to the "Open" button, click on "iOS app" and follow the instructions.
If you run into problems, open your account settings on https://my.setapp.com/subscription and click on "Manage Devices". Remove your mobile devices and try to activate the iOS app again.