Section 269SU of Income Tax Act

1. Install a swipe machine
(From your bank, paytm or other merchants)

2. Create a UPI address for your business account
(Generally like mobilenumber @ serviceprovider)

3. Generate QR code of the above UPI address
(Usually provided by the service provider itself. Can be done manually as well)

You can display them at the place of your business or you can also print them on the invoices as well.