Hello Akash 

There are some standard engineering entrance exams you should try.

They are JEE MAINS and JEE ADVANCED.

These are a necessity for NIT and IIT and GFTI.

Besides these there are other good exams like 

BITSAT,VITEEE ,COMEDk,SRmJee etc

You can also try other state CET's depending upon your state.

Hello Akash,
I would recommend you to go for JEE as all the top B.Tech institutes such as IITs and NITs conduct their admission process based on score of JEE Advance.
In order to appear for JEE Advance you have to first clear JEE main examination which is not that easy if you take it lightly.
In order to get proper guidance to clear this exam you can join online crash course by Entrance 360 where you will get number of video lectures, test series and much more.
To register for this course you can visit following link,
https://www.entrance360.com/knockoutfull-jee-main-april/?utm_source=google-search&utm_medium=paid&utm_campaign=knockoutfull-jee-april
All the Best.