As per Revenu Quebec:
*The payment code is shown on documents we send you (such as a notice of assessment or form). It is also available in My Account for businesses.
The letters “I” and “O” are never used for the first three characters of the alphanumeric code, to avoid confusion with the numbers 1 and 0.
An alphanumeric code for a payment you must make to Revenu Québec.
You need this code to make a payment using the online services of a participating financial institution.
You can pay your balance due online or by cheque or money order. If you used software to complete your income tax return, you can print a remittance slip using the same software.
If you would like to make a payment in person at your financial institution, you must order a remittance slip and use the slip to do so.