When it comes to permissions in Mura CMS, the most important thing to keep in mind is that all permissions are "group-based." So, instead of thinking about individual users, it's better to think in terms of groups. This concept applies whether we are talking about restricting access to a specific section of your site, or we are talking about "editing" privileges for various groups throughout your website. As you'll see, you can always create a group with only one individual assigned to it, if you really need to only allow one person access to something in particular.
That said, Mura CMS has included some very powerful features to assist you in setting up your desired permissions for various sections of the administration area, including the rights and privileges each group has when it comes to creating and managing content, or even accessing different areas of the front-end, public-facing side of your site.