Hi Shruti,

To attempt JEE Main mock test, I will not recommend any third party app as NTA(National Testing Agency) itself has a mock test section on its official website.

Website Link - https://nta.ac.in/Quiz

Just copy this link, and paste it in your browser. Then select JEE Main exam and any relevant shift. Then LOGIN using the sample login menu and read instructions to start the mock test.

Feel free to ask doubts in the Comment Section.

I hope this information helps you.

Good Luck