Hii!
The NEET UG 2021 application forms are not yet released but are expected to release soon on the official website ntaneet.nic.in
You can check the official website for updates. The application forms can be released anytime soon most probably by this week. The link given below will help you with more information.

https://www.google.com/amp/s/medicine.careers360.com/articles/neet-application-form/amp

Hope this helps.
Good luck!