If you're using an Android device, the general payment method is Google Play. In your Google Play settings, you can add a payment method of your choice, which will then be used when you make a payment in the game. Here's how to do so:
On your Android phone, go to your payment methods in Google Play.
Tap "Add a payment method."
Choose the payment method you want to add.
Follow the on-screen instructions.
If you need to change the payment method, follow these instructions:
On your Android phone or tablet, open the Google Play app.
At the top right, tap your Profile Icon.
Tap Payments & subscriptions > Payment methods > More payment settings
If asked, sign in to Google Pay.
Under the payment method you want to remove, tap Edit.
Make your changes.
Tap Update.
If you need to remove a payment method, you can do so in the same menu.
Please visit the official Google Play Help page for more information if needed: https://support.google.com/googleplay/answer/4646404?hl=en&co=GENIE.Platform%3DAndroid.