The Paytm mobile app automatically detects the Mobile operator while entering the number. Once you have put number and amount, it will proceed to next page, where you can see Promotional/Voucher code. I like Paytm app and use tjis app always. It is good for coupon lovers. Here, you can get discount on various products, while opting it. Otherwise, you can also skip this step. Once you have done this step, you will be land on another page, which is Payment page. Here, you have to fill all of your Debit cards details and will click on Proceed Securely button. Your transaction have been completed. If your transaction has failed then you got a page that will confirm you a retry of the same recharge or start with a fresh recharge by editing the previously entered details. There are many other payment mode options available on the Payment page, like Credit Card, Net Banking, ATM Card, IMPS and Cash Card.