I used three or four capital letters used in my signature in neet application form any problem

Hey aspirant , hope you are doing well
As i can see you are worried about the signature , so i can assure you that you aren't going to face any problem as signature is a signature and it doesn't matter how you do it . But you should always make sure to do the same original signature of yours at all times to avoid any confusions.
If NTA found any problem in the signature in application they will send u to correct it in mail.So that you need to do immediately the next day. But as we know the correction window is closeld , so we can assume that your signature was accepted without any faults.

Also the signature in your admit card and your attendence sheet should match to avoid any problems but in most cases , there aren't any complications faced by a student due to his signature.
Also , just so you know , the signature should always be in runny handwriting and you should practice it as its going to be the official one and you are gonna use it for rest of your life.
Here's a link to get latest news about NEET 2021 https://medicine.careers360.com/articles/neet-application-form
Hope this helped
Thank you