For a short while there was a Code tab in the discount section of the POS app on iOS. It was very handy but vanished after a short time and has not come back. Is this feature ever going to make a return? We often run sales that only include a small subset of our items so being able to use the code we created is much easier when a customer is buying a mix of sale and non-sale items. In our situation it is further complicated by customers being able to buy fractional amounts of most of our products so the item specific discount gets used for that.
Freddie here from the Shopify Support team, happy to help.
This isn't something that should be happening to your store, as you should be able to use this discount field still within your POS systems. Our team will need to investigate directly into your store, so I have sent you an email with further information on how we can get you authenticated with the account in order to look into this and help resolve the issue on your store. Be sure to check your email (the same email address that is associated with this Forums account you have posted from,) and respond to me as soon as you can.
Shopify Support - email@example.com