Sign in with Apple

You can sign in with Apple in the license detail screen on macOS or iOS so all your devices have the same ID and can be linked to a Stripe subscription:

macOS
Open the settings (CMD+, or see "NotePlan" > "Settings..." in the menubar), then click on "License".
Note: Signing in is not available in the TestFlight Beta. Use the App Store version to sign in, then return to the TestFlight version.

iOS
In the left sidebar scroll to the bottom and tap on "Settings", then on "Subscription Details" at the top. On this screen you should see a button "Sign in" / "Sign out".

Once you sign in, the User ID at the bottom changes. Make sure to sign in on every device you want to use NotePlan on. To connect and sync between devices, you need to use the same Apple ID.