admin/config/people/accounts/fields not displaying I am new to drupal and have inherited a site.
I want to tidying and edit some of the fields n the user profile that already have been added, however 
admin/config/people/accounts/fields does not appear as a tab in admin/config/people/accounts
and nothing happens if i try to access admin/config/people/accounts/fields directly.

How can I enable this tab?
The page you are looking for is provided by Field UI core module. Go to /admin/modules and enable it.