I've followed the steps described in Change your Apple ID payment method if you don't have an Apple device - Apple Support
Everything is fine and it's okay to subscribe using my default payment method with gmail.
But when I tried to find "Payment Information" (No.4 step under "Change your payment method on your Android device or Google Chromebook"), I couldn't find it under Account.
Please help
If you are having problems in updating your payment information with the non-Apple device you can sign onto the Manage Apple ID page with an Internet browser and navigate to Payment Methods in the column on the left of the page. Then click on Manage Payment Method on the right of that page.
From there update your details.
If you are having problems in updating your payment information with the non-Apple device you can sign onto the Manage Apple ID page with an Internet browser and navigate to Payment Methods in the column on the left of the page. Then click on Manage Payment Method on the right of that page.
From there update your details.
How to change payment method via Android Apple Music app
