Organizations with multiple users can set rules for their editors and managers so they can only access those Folders they're given permission. For each Folder, including the top-level Site, a Sharing Tab is available to invite users to administer the section.
To get to Sharing, go to Site Settings from the site panel, and then to the Sharing tab.
Once the Sharing tab is selected, a panel will slide out with a list of the shared users and invitation form.
For the top level under the Site Settings Tab, a table of all site users and their Folder permissions are listed to provide an overview as well as a way to Unshare access.
Invitees with an X in the Request column means they're invitation is outstanding and they have not yet accepted your request to share a site or section. Invitations Requests expire after 3 days.
After an invitation is sent, the recipient will receive an email to accept the invitation. This step is required before they may access your Sitemason account.