Account created with email or Facebook login
If you created your account with your email address or used the Facebook login option, you can easily log in to additional devices. It doesn't matter if they are iOS or Android devices.
Account created with Apple ID
The "Sign in with Apple" option is only available on iOS devices. So if you have created your account with this option, you can only use it on iOS devices.
Use tonestro Premium on another device
A Premium subscription is tied to your account and not to a specific device. Therefore, if you login with a Premium account on another device, you will have all the Premium benefits there as well.