I have scored 42.43 percentile in jee Mains. which branches and which college I can eligible.

Hello student you can calculate and get your rank by using this formula.
(100-your total percentile) 869010 /100.
In your case your rank must be around 500289.
As the cutoffs are not out yet also its vary year to year on various things like level of question and numbers of aspirant.
I'm considering you as a general candidate because you've not mentioned your category with this rank its difficult to get admission in any good Goverment college as we all know that seats are very limited and admission is directly based merit rank.
I request you to please help me with your category so that I can provide you exact information.

Application for jee main April start from 07th of February and shall remain open till 07th of March 2020.

Feel free to comment if you have any doubt
Good luck