If you are enquiring about NEET 2021, though we still have time for the official notification to be released we shall explain the Application process for you.

There are 5 stages in the Application process:
Registration
Filling the Application form
Review and Final Submission
Upload Photograph and Signature
Pay the fees
Take a print out of the Confirmation mail

Registration:

All the communication from NTA will be online and through email so it is important to give an email id and mobile number that are in regular use. You will have to fill in the details like Candidates name, Mothers name, Fathers name, Date of Birth, Gender, Nationality, State of Eligibility, Category, PWD, Identification Type, Identification Number, Mobile Number, Email Id, OTP.

Filling the Application Form:

You need to fill in details like Personal Details, Place of Birth, Choice of Medium of Question Paper
Choice of Examination Centre - four exam cities have to be chosen, 10th Academic Details, 11th, 12th Academic Details, Permanent Address, Correspondence Address
Details of Parents and Guardian, Dress Code Assent
Security Pin

Review and Final Submission: There will be a correction window open but not all the details can be edited. So it is important to review the information before submitting it.

Uploading of Photograph: Instructions

Must be postcard size picture in a white background with the Name of the candidate and date written on the photograph. The Size must be 10 Kb to 100 Kb and format should be JPG.

Uploading of Signature: Instructions

Candidates must sign with a black pen on a white background in JPG format with a file size of 3 Kb to 20 Kb

Payment:
It is Rs. 1400 for General/OBC and Rs. 700 for SC/ST/PWD/TransGender and the Payments can be made through Debit/Credit Cards or Net banking OR offline through SBI Echallan to be paid in cash in the nearest SBI branch. This might change or might remain the same for 2021.

Print out:
Take a print out of the Confirmation page for all future references

Now regarding your documents, you will need to upload the scanned documents of your 10th and 12th marks sheets. So you ma have to reach out to the College administration asking for documents for a day or 2. Most Colleges take an undertaking stating that you will return the originals in a day or 2. Once you submit this letter, they will give you the original documents.  You can get them scanned and xeroxed and keep a few copies with you for future reference. And during Counselling, you can request the College for the original documents and they will give them. So there is nothing to be worried about it.