I am making a ticket selling web app(mobile) where a user can buy a ticket and a digital copy of the ticket will be shown with some details, what I want is to integrate a payment method (specifically for Indians because of UPI) in which the user can scan a qr-code or send payment req to the upi-id and the user should be able to pay (any other suggestion on the method of payment will be appreciated) now the problem is how to do it in a way where I don't need to pay any services at all or is it even possible to do so without paying any services?? since I am very new to this topic of payment I don't know where to start so any suggestion of a direction will be appreciated.