How do I create a back office for my website using Wix?

Hi Mosa,
There is a lot of stuff regarding this on the forum. Use the sign button above to use it.
Can you please elaborate ?

I would like to create a portal site for my clients, so that they can sign up and login and view their investments, showing how much they deposited, growth of their account using a line graph.

Check out this article about creating your own members area.