Hello Sushma,
As a prompt answer:
Input form: is like the input schedule in old BPC version (7.X): it is kind of input sheet where you can send data to your DataBase.
Report: is a sheet where you can retrieve data from your database: you cannot send data via a report. You will find the button grayed out.
Workspace: you find it in BPC Web, it is a menu with all the components that you are authorized to access and so groups specific content. It behaves like a folder, which contains Planning and Consolidation items, such as reports, input forms, Crystal Dashboards, and so on...
Best Regards,
Noura