I would like to add some additional functionality in Users page, like adding profile related data which we are creating separately suppose, mother tongue, address, hobbies , and job related in same page of the User, can we somehow override the main users page in back-end admin dashboard to show these details as well along with main user data. Also the admin should be able to create/modify or delete it. Can you help me in this issue, I'm not able to redesign the page.
I might be misunderstanding your question, but you can choose which columns are shown on all of Craft's element index pages using the little cog at the bottom of the sub-nav sidebar. You can also add additional headings to the sidebar and rearrange them from here.
For non-superadmins, you need to grant permission for them to access this functionality by enabling the
Customize element sources permission under Settings > Users > [User Group] > General.