I was wondering if when I create a custom template for a page and some other categories in the sidebar eg other than the search bar, catagoiries, posts , I add to it about us or a text advert. Will all of the new sections created in the sidebar automatically be editable or will a client need to know html php to edit the new sections?
It depends on what you add. If you are just adding some text. Then anyone that can read/write (and knows where to edit it) can edit it. If you're adding in code, than some level of knowledge will be required.
You can use the text widget to add pretty much anything to the sidebar.
Hope this was what you we're asking, if not post again.