MACH is a mobile payment app that allows you to buy online in China and pay in stores in Chile. If you are interested in purchasing online, the first thing you should do is download the app on your phone or tablet. Once you do that, you will be able to see the available payment options. Next, you will need to choose the payment option that you prefer. After that, you will need to enter the billing information of the store that you want to pay in. The last thing you need to do is to confirm the transaction. Once that is done, you will be able to see the amount that you have paid.