1.) Go to the Facebook Ads Manager website (https://business.facebook.com/ads/manager) and log in to your Facebook Ads account with your Facebook credentials. Once logged in, you will be taken to the Ads Manager dashboard. 2.) In the left-hand menu, click on the "Billing" tab located at the bottom of the menu. 3.) Under the "Payment Methods" section, you will see the current payment method(s) linked to your Ads account. Click on the "Add Payment Method" button if you want to add a new payment method, or click on the "Edit" or "Remove" button next to the existing payment method if you want to update or remove it. 4.) Follow the on-screen instructions to add a new payment method or update the existing one. You can choose from various payment options, such as credit/debit cards, PayPal, UPI (Unified Payments Interface), and more, depending on the available options in your region. 5.) If you are adding a new payment method, enter the required information, such as card details, billing address, or UPI ID, and click on the "Add" or "Save" button to link the new payment method to your Ads account. 6.) If you are updating an existing payment method, make the necessary changes, such as updating card information, and click on the "Save" or "Update" button to apply the changes. Once the new payment method is added or the existing payment method is updated, it will be reflected in your Ads Manager account, and you can use it for making payments for your Facebook Ads campaigns