Hiiii Pranjal,

I would like to inform you that the last date of online application form submission, uploading of scanned images and payment of fees was due on 7th March 2019. Hence even if you filled the form but the payment isn't made, you can't appear for JEE Mains 2019 anymore. You can only apply for JEE Mains next year. 

But I would like to acknowledge you about the various other exams through which you can get into various engineering colleges. All you need to do is go through their official site and fill up the registration form for the respective exams.

Here is the list of examinations you can refer to for admission into an engineering college:

BITSAT examination - With this exam, you can get into Birla Institute of technology at Pilani, Goa or Hyderabad.  These institutes have private ownership and have placements equivalent to Indian Institutes of Technologies.

MAH-CET - With this exam, you can get into Maharashtra Institute of Technology, Pune and many other engineering colleges of Maharashtra.

TNEA - With this exam, you can get into Anna University and many other colleges of Tamil Nadu.

VITEEE - With this exam, you can get into Vellore Institute of Technology which is one of the top private engineering colleges offering high placements.

SRMJEE - With this exam, you can get into various campuses of SRM Institute of Science and Technology, the main campus being located at Chennai.

COMEDK - With this examination, you can get into various engineering colleges of Karnataka such as RV College of Engineering, MS Ramaiah Institute of Technology, PES University and many more.

WBJEE - With this examination, you can get into various colleges of West Bengal such as Jadavpur University, Haldia University of Technology and many more.

EAMCET - With this examination, you can get into various colleges of Andhra Pradesh such as Jawaharlal Nehru Technological University,  Vasavi College of Engineering and many more.

I hope I have answered your question. For any other query, feel free to contact anytime.

Thank You and all the best for your endeavours ahead.