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

Okay, right, I need to pay my doctor's invoice. I went the website and it says I need a client ID. But, I don't have that! What am I supposed to try? Is there a way to access my client ID? Can someone figure this out. It's really annoying having to pause payment because of this. Using Veradigm & Pay My Doctor Navigating healthcare expenses can b