No the application form for JEE main April session will begin from February 8 onwards therefore from February 8 onwards you will be able to register for JEE Main April Session.

Hey Aparna.

For the April Session of JEE Mains, the application process will start on 8th February, 2019 and will last till 7th March, 2019. So you can apply for it when the application is released. You can use the link below for updates.

https://engineering.careers360.com/articles/jee-main-april/amp

Best of luck!