A confirmation page is another term for “fax receipt.”
It is a receipt to show that a successful transmission.
When sending a fax, the receiving fax machine sends a signal saying “message entirely received” when the transmission is one.
When the sending fax machine gets the “message entirely received” message, it prints out a confirmation page.
The confirmation page contains date and time the transmission started and finished, who send the fax, information on where the fax was sent and may include a copy of the first page of the fax or even all pages of the fax.