Quebec businesses that exceed the small-supplier threshold may need to register for GST and QST and collect both taxes on taxable supplies.
Invoice records should keep the taxable subtotal, GST amount, QST amount, and customer details in a format that supports bookkeeping and remittance.
If you sell across provinces, tax treatment can depend on the place of supply and whether the customer is in Quebec or another province.
Rates and exemptions can change. Always confirm the final treatment with Revenu Quebec and CRA guidance for regulated or unusual transactions.