Add a page where people can write something.

I want a page where people can write someting and then save.
For my business website i want the everyone have in his profile a butoon that leads to a page.

this page can only be seen by himself and other paid members.

Thank you. 

It is highly unlikely that anyone is going to spend the time to code something like this for free and post it here. I would suggest you post it as a Job.

I just realize there doesn't seem to be a Jobs board here anymore.

Have you looked at AntonLV "Pages" module... https://www.boonex.com/m/pages yet?  I haven't used it but the description appears to include what you're looking for.  And 'no' I don't get a commission for suggestion it.  If I know of similar *current* modules by other vendors I'd have mentioned them too ;-)

What about the Blog included with Dolphin? Sounds perfect to me. Alternatively Modzzz has a module called Stories which may do the job.

 If you type it in the URL Address bar; https://www.boonex.com/jobs, the page still exists.  I don't know if there is a link anyway though.

It is still there: Help > Jobs