1. Open your Google account.

2. Click the "Profile" icon in the upper right corner of the screen.

3. In the menu that opens, select "Payment".

4. Click "Add payment method".

5. In the pop-up window, select the payment method you want to add, such as credit card, debit card, PayPal, etc.

6. According to the payment method you choose, enter relevant information, such as card number, expiration date, security code, etc.

7. Click the "Save" button.