Hi @Rahul_Madhyastha
I am happy that our previous conversation helped you: False “Road Closed” Reports on Google Maps—Request for Stricter Verification (Surathkal, Mangaluru) - #13 by ErmesT
However, as yo can clearly read in the website already linked by me and now by @MortenCopenhagen
Here is the list of the type of partners: Who we work with - Maps Content Partners Help
If you are part of one of those categories, you can join from here: https://contentpartners.maps.google.com/start , otherwise you should involve someone of the categories mentioned above for them to join.
I am a partner myself, on behalf of a Local Administration in Italy. Of course they issued an official document to give to my Non Profit Association the legal rights to upload their data in Google Maps.
Otherwise there is no way to join, not because you are not good, but because Google needs the greenlight from the Local Authorities to modify the Map of their area