When you use the Email Experience Manager in multisite environments, you must differentiate between the sites and their manager roots. A manager root contains all the settings that control the user experience of the component. You can create additional manager roots manually.
By default, the component searches for the manager root under the item defined in the Default Root Parent setting of the /sitecore/system/Settings/Email item.
The location of the manager roots is defined in the /sitecore/system/Settings/Email/System/Root List item. The module updates this item automatically.
A user can have access to several manager roots. You can use standard Sitecore security applications to grant users permissions to specific manager roots.