Does my portal tell my customer whether a ticket can be changed or refunded before they pay for it?

Yes, in most cases. Airlines attach a set of fare rules to every fare they sell, and those rules say whether the ticket can be changed, whether it can be refunded, and what the airline charges for doing either. Your portal can pull those rules through with the fare and show them on the page where the customer reviews the trip, so they can read them before they reach the payment step.

How much detail appears depends on the supplier behind the fare. Some suppliers send back a short, tidy summary that reads well on a booking page, saying plainly that a fare is refundable or not. Others send the airline's own wording, which is long and written for the trade rather than for a traveller, and the honest thing to do there is show it as it came rather than shorten it and risk changing its meaning.

It also helps to remember that the rules describe what the airline allows, not what it will cost on the day. A fare may be changeable, but the customer still pays the airline's fee plus whatever the new fare costs at that moment, and that difference is not known until they actually ask to change. Saying that clearly at the time of booking saves an argument later.

Look at one cheap fare and one flexible fare on a route you sell often, and check what your booking page shows about changes and refunds for each, so you know what your customers are seeing before they pay.