Yes. Episerver is a framework where you (or your developers/partner) are responsible for defining and develop content types and views. Everything is possible, almost. 

Thank you for your reply. Just to be clear: I meant that you only have a single license, and that you create different footers on different sub-sites within that same license.

I guess that's how you interpreted it and that the answer is still the same; that it's possible and just a matter of how you define and develop the conent types/views. Right?

The license is bound to a server or instances (in the cloud) and also contain the number of websites you can have. A sub-site (child page, sub folder or whatever you call it :)) is not a website, so it doesn't count against the number of websites in the license. A website is something you create in Episerver admin mode and each website has its own startpage, i.e. cannot be a sub-page to an already configured website.

Thank you for your quick reply! Okey, I thought that one license only could contain one website, and that if you wanted several websites you had to buy several licenses. Originally, I wanted several websites, but because I thought that several websites meant several licenses, I started looking in to the option of having them as sub-sites within a website, and what limitations that meant for the design of the sub-sites (for example regarding the footer). 

Hope I'm making myself clear :)