Most airlines give between a few hours and 24 hours on an unpaid reservation. Some deeply discounted fares give far less — occasionally under two hours.
The exact expiry for your booking is shown on the reservation page and repeated in your confirmation email. Treat that time as firm: airlines cancel unpaid holds automatically and we cannot reverse it.
If you are close to the deadline, send the transfer and press I have paid. Declaring payment protects the reservation while we verify.