Question: To add a promo code to your Uber order
Option 0: Open the Uber app.  Tap the History button.  Tap Payment.  Tap Add Promo/Gift Code.  Type in your PROMO CODE.  Tap ADD.
Option 1: Open the Uber app.  Tap the menu button.  Tap Payment.  Tap Add Promo/Gift Code.  Type in your PROMO CODE.  Tap ADD.
Answer: 1