PayTM is only for Private Ltd. companies. Unlike PayPal(unfortunately not in India), which provides access to there SDK for developers as well.
If you want to integrate PayTM, you would have to contact them and they will give you a list of things (which includes: DIN number, company name, PAN.. etc) which you should have before getting the SDK access.
This to me is pretty outdated thing. PayTM should provide access to developers to at least test their platform. Sandbox account is something developers can test their app before going live they can definitely request for all the needed details. In that sense, PayPal integration is way way better.
@Prerna Kalra Please let your team know that developers want to test their integration before going into all the official details.