Paying In-Person: The Canada Post QR Code Method

If you prefer to pay with cash or debit in person, the CRA has partnered with Canada Post. You can generate a QR code from your CRA My Account or through a third-party service like PaySimply, then take it to any Canada Post location to make a payment. It's important to remember that Canada Post may charge a service fee for this transaction. This method is a convenient option if you need to pay with cash or prefer an in-person transaction.

Source: https://www.canada.ca/en/revenue-agency/services/payments/payments-cra.html