To check the last 4 digits of the credit card on your account, you may follow the steps below:
1. Go to Accounts & Billing.
2. Click on Payment methods tab. From there you will see the last 4 digits of the cards you added on your account.
Why Knowing Your Credit Card or Debit Card Number Registered with Bing is Important?
In case you have to provide an access of your account to a marketing executive of Bing Ads; you have to provide the information of just one card so that they could verify your account and check your campaign status.