Select an email message, go to the Home tab and click 'Convert into'. Select Task, Issue or Request to create an activity of a given type. To convert an email letter to a project, select Project.
A task or project creation window will open. After selecting a project the email recipients will be automatically assigned to the activity or added as project members if a project is being created.
If the email letter contains attachments, they will also be added to the activity or project.