Hello Nitish

UPSC NDA-II 2020 Application Forms were released on June 16, 2020 and candidates could apply till July 06, 2020.

This year  NDA-I and NDA-II will be conducted together on September 06, 2020.

For more news on NDA you can visit https://news.careers360.com/nda-2-application-form-2020-out-apply-online-for-413-posts

As for the best institutes for nda preparation you can try Siegwald Academy , Doon Defence Academy (DDA) Dehradun , Anees Classes , Warriors Defence Academy (http://www.warriorsdefenceacademy.com/) etc. However most people crack the written exam without any coaching and the best institutes also depend on the state.