While creating new user from postman it shows error:
Insufficient scope, expected any of: create:users
Like mentioned in the error message the access token that was provided does not have the scope required to perform the associated operation; creating a user requires the create:users scope.
You mention Postman so I’m assuming you’re just testing things so you may want to check the reference documentation (it explains the scopes situation) on how to manually obtain a Management API access token: