Your question is a bit vague, so I will respond based on how I'm intepreting it, which is ...
" I would like to display a summary view of the data stored on our Tableau Server. I want to include the following information : total number of views, total no of workbooks, total number of users, total number of projects".
All of this information is available on Tableau Server on various screens, but not on a single display/dashboard, which is what I assume you want.
Therefore, you will need to create your own dashboard which sources from the Tableau postgres database to access the information you need.
To open up the Tableau database (the repository) see here Re: Tableau Server Postgres Repository (Note this is relevant to v2018.3 as it uses TSM - you may need to reference other docs for earlier versions).
To understand what's in the Tableau postgres database , see here Re: Tableau Server Postgres Repository
Hope that gets you on your way
Actually i want the report card it should have the total reports,total work books,and total projects i need this all should display in one report
Apologies, but I don't understand what you mean by 'the report card'.
You're going to need to develop something yourself, that connects to data from the postgres database, and presents the information on a dashboard for you to publish to Tabeau server. All the information above should help you get to what you need to do this.