When size, weight, or other factors prevent sending an enclosure with a letter, send it separately and type "(sep cover)" after the enclosure's description. 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.Add an enclosure notation after your signature at the end of the letter, and abbreviate it with "Enc." or "Encl. Do you need a Release or Waiver Agreement Form in Pennsylvania? Create, print or download your Pennsylvania Release or Waiver Agreement form for free. Release Effective in Pennsylvania. As a general rule, releases of liability for negligence in a recreational setting are valid and enforceable in Pennsylvania. Add an enclosure notation after your signature at the end of the letter, and abbreviate it with "Enc." or "Encl. Choose a few phrases in the opening paragraph that let your reader know what to expect in the body of the letter. See sample form 20 for combined release in Appendix. 5.