The short message usually included in sending a formal report, proposal, brochure, or other similar material is called a letter of transmittal or a covering letter. Occasionally, it substitutes for a summary at the beginning of the report.
A letter of transmittal is given in a letter or memo form which provides extra personal touch to formal reports. It is brief and follows this pattern:
• an opening statement, “transmitting” the report to the reader and stating its purpose
• a brief outline of the major conclusions or recommendations
• a note of gratitude for any special help received from other employees
• a goodwill close which looks forward to future discussion or opportunities