Hey Aspirant,

You can retrieve your NEET's Application Number easily by following some steps;-

• First go to the NTA website  https://ntaneet.nic.in
• Click on the link NEET (UG) - 2021 - Find Application No
• Enter the accurate information which you have put in the NEET Application Form at the time of the Form Submission.
• Enter the ‘Candidate Name’, Father’s Name, Mother’s Name, Date of Birth, Category, and Security PIN.
• Click on Submit
• You will get the application number on the mobile number which has been registered.
• After that you can do the payment.
• Make sure that you save the NEET Application Number so that you do not lose it again in future.

Hope  it helps.

Regards.