This feature is part of Practo Ray Pro.
How can my customers redeem a SMS offer or avail discounts?
The prefilled SMS text that you send to customers contains an offer code. In case you choose to customize the text, we recommend that you include the offer code in your SMS. You customers can show the offer code to the billing desk and redeem your offer.
How do I add an Offer discount while billing?
While billing your customers for services rendered, you can add your discount by clicking on the Discounts down-menu. From here, you can choose the discount that you want to add to the bill.