Selection.GoToEditableRange (Word)

Returns a Range object that represents an area of a document that can be modified by the specified user or group of users.

You can also use the NextRange property of the Editor object to return the next range for which the user has permission to modify.

GoToEditableRange (EditorID)

EditorID: Can be either a String that represents the user's email alias (if in the same domain), an email address, or a WdEditorType constant that represents a group of users. If omitted, selects all ranges for which all users have permissions to edit.

Selection.GoToEditableRange wdEditorCurrent