Gap takes part in the MUSE points program. When registering, connect your MUSE and Gap accounts through the join MUSE or link account option, then confirm with the code texted to your phone. From then on, online orders earn points, and in stores you share your MUSE details when paying. You can then pay with points, either online at checkout or at the till.
If an order earned you no points because the accounts were not linked, the customer care team is able to add them, and according to the help page points from a purchase become spendable at most 30 days after it is made. Gap's site additionally promotes 15% off the first order placed through the Gap app after downloading it. For now, stores offer neither alterations nor gift wrapping.
Source: Gap Saudi Arabia: MUSE help