Absolutely! In fact, I encourage the owners to participate in adding content on the site. But this does take training. It honestly is not that difficult to learn how to do this if I use a content management system (CMS).
What is a CMS you ask? A CMS is a type of application but not something you would have on your desktop. You would log into the system, make your edits, save and log out. When you save your changes, your site will show them.
There are some CMS’s that are easier to use than others. I set up your site to make sure my clients have the smoothest experience editing.
To read more, see my blog post: Can the site owner edit his or her own site and what is a CMS?