The JEE Main 2019 Admit Card for April examination download is expected to begin after 12 pm on the official website jeemain.nic.in on March 20. The timing might vary depending upon different factors. Their might be some delay. But that will not be an issue. You don't need to download the admit card just at the time it is released since all the students will be trying to download .There server might be down. So, I suggest you wait for a couple of hours then you can download it quite easily. 

For ay other details you can refer to the link below:

https://engineering.careers360.com/articles/jee-main-admit-card

Hello Rajesh,

The JEE Main 2019 Admit Card for April examination download is expected to begin after 12 pm on the official website jeemain.nic.in on March 20.