UPSET PAY MY DOCTOR: WHERE'S MY CLIENT ID?

Okay, so, I need to pay my doctor's bill. I visited the portal and it says I need a account number. But, I am missing that! What am I supposed to check? Is there a way to retrieve my client ID? Please figure this out. It's really bothering having to halt payment because of this. Veradigm & Pay My Doctor: A Guide Navigating healthcare expenses ca