TRYING TO PAY MY DOCTOR: WHERE'S MY CLIENT ID?

So, I'm going to pay my doctor's fees, and it says I need a client ID. Here's the catch: I can't find it anywhere! I've looked in everywhere online. Did my doctor's office send it to me? Do they have a different website? Any tips for finding this client ID would be really helpful. Accessing Veradigm Pay My Doctor and Payment Complications Are