Most of the questions you’ve asked should all be taken care of in your contract with the client. You should be the one laying out the rules. Here’s how my contracts would answer your questions:
Do you do the webpage and the client have to be satisfied with it, or do you work together with the client until the client is satisfied? How much do you people "control" the work?
I provide one design (after approved site architecture is complete) that allows for three revisions. If client is still not satisfied, we can either add a change order (more money) or start looking for a new developer (and I get paid up to the work completed). For the most part, I maintain creative control – with input from the client.
How about the copyright of the webpage? If you´re paid (or not) for the webpage; thas it matter?
Is it just you that can make changes to the page (after you given the webpage away)?
Or is it then up to the client what he/she wants to do with the webpage?
After a client has paid for a website, they can do whatever they want with it. My contracts state that only once the ENTIRE project has been paid for does any of the copyright transfer from me (the designer) to the client. It’s up to the client to re-hire me if they want any changes to be made. If they want to hire some other developer to make changes, that’s their prerogative.
I am a little bit afraid that my client can have somebody else to do the changes, to the webpage I have made for he/she after I’ve been paid. Is that okey?
Of course, why wouldn’t they be allowed to have somebody else do the changes?
It’s so important to write up a thorough contract that covers all of these topics and more!