Enclosures. An enclosure can prevent a letter from becoming too detailed. Letter of Intent is a written agreement between the City of Charlotte.The venting system shall be installed in a conduit or enclosure with sealed joints separating the interior of the conduit or enclosure from the ceiling space. In this article, we explain what an enclosure is and how to cite one, and we provide an example of an enclosure in a business letter. ONLY Electronic responses will be accepted for this solicitation. A copy of the certification letter from the administering agency is a required enclosure with Form PTE. Fill out the Application for Probate and Letters (AOC-E-201). 2.