Hi Ramendra.

You can get admission in JAYPEE on 10+2 merit. They take students on the basis of 12th marks, but only to JUIT, JUET and JU-A. They have the details regarding their various admission procedures on their admission procedure page. They have also provided a link to helpdesk, so that you can contact them for clearing any doubts.

For admission into JIIT, you have to go for JEE.

http://www.jiit.ac.in/admission-procedures

Good Luck.