The conference will be held at NIT Raipur.
Raipur is the capital city of Chhattisgarh state and has an international airport.
Wikipedia page about Raipur.
Conference organizers will provide the invitation letter to authors of accepted papers. Delegates and other participants can request an invitation letter from the organizers. You can request a letter by writing to email@example.com with your details.
FAQ relating to conference visa (from Ministry of Home Affairs, Govt of India)