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

So, I'm attempting to pay my medical bill, and it says I need a client ID. The thing is: I can't find it anywhere! Searched everywhere online. Did my doctor's office send it to me? Do they have a online system? Any tips for finding this client ID would be greatly appreciated. Logging in to Veradigm Pay My Doctor for Payment Issues Are you exper