• You need to be at least 17 years old by December 31st, 2020
• You need to be either appearing for your class 12th board examination or should have passed it with at least at least 50 % aggregate in pcb in your class 12th board examination if you belong to general category ; while it's only 40% aggregate in pcb for obc, sc and st categories , 45 % aggregate in pcb for pwd category.
• While filling the neet application form you will be asked to to select a code for qualifying examination, in that you need to select code 01 as code 01 is for candidates who will be appearing for their Class 12 board exam in 2020 and then you will be easily able to fill the neet application form

Dear Aspirant,

Yes you are eligible for applying to NEET as you are appearing in your 12th and appearing candidates can give NEET exam.

To register for NEET 2020, candidates must enter their name, email Id and mobile number on https://ntaneet.nic.in/Ntaneet/Welcome.aspx . A password must also be created as per the given specifications which will be the password for all future login. A provisional NEET application number will be generated after registration. This will be the user ID that will have to be used to log in.

You can refer to following link for more information.

https://medicine.careers360.com/articles/how-fill-neet-application-form