It's possible for users to manage and create site's within the DMS. This function is optional and you can enable it as an Workspace 365 admin. Go to settings and "SharePoint documents". Here you can enable site management.
With site management enabled, several options can be configured. A default description can be filled in. This description will be the default description for the users when creating Subsites from the Documents app. The default language can be selected. The languages which are available/activated in SharePoint will be available. Depending on the language, different templates can be selected. Users can choose templates, admins can set this option.
There are two possible default options for the permissions. The option: "Allow user to override" will enable or disable the user's option to set the Description, Language, Permissions.
When site management is enabled by the admin, the user can switch on site management in the Document app. This is only for the user itself. Click on the wrench to toggle the function on/off. To add a Subsite, click the wrench on the desired location.
Fill in the preferred details and click done. The Subsite is now created.