What Google recommends:
It is very important to keep your Google Ads account permanently linked to a payment method for covering advertising costs. Google Ads allows changing your payment method anytime, but you must set up a new method to continue to benefit from the service. Quick tip from Google: Add a secondary credit card.
Changing the primary payment method in Google Ads:
Step 1: Open your Google Ads account Step 2: Click on ‘Tools and Settings’ button (the tool icon) and select ‘Settings’ in the ‘Billing’ category.
Step 3: Navigate to the “Payment Methods” tab in the side menu.
Step 4: Remove your current payment method by clicking the “Delete” button, then add a new one using the “Set Primary Payment Method” button.
Note: If you can’t delete your current payment method, it’s likely linked to other subscriptions and services.
Step 5: Choose an existing saved payment method or add a new one. 
