www.wysiwygwebbuilder.com

What is your favorite solution for membership site ?
OR is it better to use CMS like W**dP***s ?

Depending on what you want PHPJabbers have a script at https://www.phpjabbers.com/member-directory-script/

I was looking for WB extension

What exactly do you mean by 'membership site'?

Do you mean this?
https://www.wysiwygwebbuilder.com/login_basics.html

Thanks for replying but no,...
I thought this is obvious question. No the link you posted is just registration. Membership is always (or almost always) paid. There are also access levels involved. One can go anywhere on-line and search for membership site. It is not a rocket science. I could probably program this myself but it would eat up to much of my time so I am looking for solutions. I think I saw a WB extension like this on somebody's site but can recall where or have access to it anymore.
I'm also not familiar yet how the WB forms work, but perhaps such a thing can be implemented with those forms.

There is no standard solution for this, this will require a third party script.

Of course there is no standard. I can use forms for most of the features needed. The main question is how to restrict users content based on some criteria (i.e Membership variable=1 OR 0) ? I am not familiar with how WWB generates and validates passwords so I can eventually connect my external App and place it in an iFrame. The first thing to figure out is how to authenticate user ?

The built-in login scripts can be fully customized.
However, I cannot help you edit the code, because for me that would also take a lot of time.

If you want to use the built-in login tools then I recommend to first make the basic system work and then make the modifications you need.