A commercial invoice is a document used for customs declaration in the sale of goods that are exported across international borders.
A credit note is a document issued to the buyer if goods are returned due to damage or mistakes.
A timesheet invoice is sent to a customer to charge them for work done or services rendered on an hourly basis.
A retainer invoice is sent to a customer if they make an advance payment for a product or service. This amount is then deducted from the customer's final payment on delivery or completion of work.
Recurring invoices are created and sent to customers at regular intervals, for repeating transactions like subscription fees.