Companies have the option of offering bonuses for the shifts they post on the WorkWhile app. You'll be able to see whether a shift offers a bonus before accepting it. If you accept and work a shift that has a bonus, the bonus payment will be processed 24 hours after the scheduled end time of that shift along with the shift payment.
Please note, shift bonuses are only issued once you have worked and completed a shift. If the shift is canceled with late notice, you will only receive the base pay.