Paytm mobile app is a great app you will find this app on most all the smart phones . You dont have to carry cash and pay people. Ever since the demonetization has happened you see there is a great crush of cash every where . Patym is just a wallet where you can keep your money in it. You can use net banking or a debit card or credit card to fill that wallet . When you actually go out and want to buy something like food or grocery all you need to use this app. It has a bar code you align it with the bar code of the retailer you are paying too and the money is transferred to their wallet. It might just sound complicated but it is very easy to use. Even the smallest of the smallest vendors have paytm. If the vegetable vendors who sell vegetables on hand carts also use patm. It is a very convenient and a useful way of using money digitally .You can also pay mobile bills, DTH bills etc