Hello Arun!

First of all specify filling which exam application form you made mistake. However if have commited mistake in filling application form for JEE Mains April 2019, then i can help it out. 

This year JEE Mains is conducted by National Testing Authority (NTA). NTA has released list of important dates for the JEE Mains Exam. There is time period for correction too. If you have made any mistake while filling form, you will get chance to rectify them. The date for correction in application form is from 12March to 15 March, 2019.

Here is a detailed list of important dates:

• Filling application form start from 8 February,2019.
• Last date of filling application form is 7 March 2019.
• Last date of uploading scanned images and fee payment is 8 march 2019.
• The collection period he is from 11 March to 15 March 2019.
• The date of issue of admit card is 20 March 2019.
• JEE main 2019 April will start from 7 April to 20 April. 

Hope this will help you.

Thank You.