If you bought a subscription for iOS, you can change your card info in the settings for your Apple ID.
If you bought a subscription in Google Play for Android, you can change your card info in the settings for the Play Store app.
If you bought a subscription at bookmate.com or in the Android app (but not through Google Play), you can change your card info in your profile settings on the website:
1. Log into the account you were using when you created the subscription (if you are using the Android or iOS app, go to your profile settings and tap “Manage subscription.” You will be automatically redirected to the Bookmate website)
2. Mouse over or tap your avatar (the round icon in the upper right corner)
3. Select “Manage subscription” in the pop-up window
4. Select “Manage” next to the subscription for which you want to change the payment information
5. Press the pencil in the “Payment information” section
6. Enter your card info and press “Save”
If you have forgotten which method of payment you used to purchase the subscription, go to the “Manage subscription” section on the website.