Chord ai does not store any account information. You may notice that there is no login screen in Chord ai. Your user data is retrieved and sync across iOS / iPadOS / MacOS devices through your Apple account and iCloud. Same goes for your purchase information, which you can consult in your account settings

Chord ai is also available on Android but the two apps do not share any information, which means that there is no user data sync between iOS/iPadOS/MacOS and Android. If you wish to subscribe to Chord ai Pro on both OS, you will have to subscribe on both iOS/MacOS/iPadOS and Android.