Yes, you can host sites for your friends on your Web Hosting account, as long as you are not charging them money for hosting.
However, if any of your friends need direct access to the databases or cPanel functions, they will need your cPanel login information. If you chose to get a Reseller account, then each friend will have their own cPanel. This is really a much better way to host multiple sites that do not have the same owner.
Remember, shared Web Hosting accounts may not resell their hosting to other people. If you wish to resell hosting, you must use a Reseller Hosting account.
