Dear Varun

Follow the answer provided by shefali. And one more thing I want to say is some exams like you need to book a slot there won't be exact that then after booking a slot. You can take  that exam. 

Please follow the below link,  if you want more details

https://engineering.careers360.com/exams

All the best. 

You can check the entrance exam details below

JEE Main

Offline- April 8, 2018

Online- April 15 and 16, 2018

BITSAT- 16th May to 31st May 2018

VITEEE- April 4 to April 15, 2018

SRMJEE- 16th April to 30th april 2018

Amrita

Online- 19th April to 22nd April

Offline- 22nd April to 28th April

To check complete details you can also refer below link

https://engineering.careers360.com/exams

Good Luck!!