A flight confirmation, or booking confirmation, is what you receive as a receipt and record of your flight booking. It will contain a record of the flight(s) that you've purchased, pricing for your booking, as well as a 6-digit confirmation code (your PNR and/or Record Locator codes).
It is sent by whomever you booked with online, like an airline or travel site. For example, after you booked with Jetblue, you'd receive the following email:
By simply forwarding this email to us, you'll have initiated the claim submission process. Claims are then validated on our end. Once approved, we'll let you know!