Is there any developer doc link to know the all the fields available for dropbox user and group

You can find the documentation for the Dropbox API, including all of the request and response objects/fields, here: https://www.dropbox.com/developers/documentation/http/documentation

 

For example, the "returns" section of the /2/users/get_current_account documentation shows all of the fields returned when requesting the information for the connected account:

• https://www.dropbox.com/developers/documentation/http/documentation#users-get_current_account

Likewise, the /2/team/members/get_info_v2, /2/team/members/list_v2, and /2/team/members/list/continue_v2 documentation has return information about the types and fields returned about team members for the connected team:

• https://www.dropbox.com/developers/documentation/http/teams#team-members-get_info
• https://www.dropbox.com/developers/documentation/http/teams#team-members-list
• https://www.dropbox.com/developers/documentation/http/teams#team-members-list-continue

And similarly, the /2/team/groups/get_info endpoint documentation covers information about groups:

• https://www.dropbox.com/developers/documentation/http/teams#team-groups-get_info

 

These are just a few examples of course, so be sure to review the rest of the documentation there for whatever other particular functionality you're interested in.