There are many branches which you can opt for after clearing your JEE Main exam.

You should choose the branch according to your skill and interest. 

If we compare the branches the CSE is the most demading branch among students followed by ECE, Mechanical, Civil, Electrical and IT. 

Cut off also varies according to the branches. You can check the cut off through JEE Main below

https://engineering.careers360.com/articles/jee-main-cutoff

You should focus on to get top colleges to get good knowledge and placement which is very important.

Good Luck!!