Could anyone please let me know how to change the email id of users on Dropbox account?
Are referring to using the user-linked Dropbox API (for the single linked user), or the team-linked Dropbox Business API (for any particular member of the team)?
The Dropbox API doesn't allow you to change the email address of a user's account, but a Dropbox Business app can be used to change the email address on a team member's account using /2/team/members/set_profile.