A transmittal document is a kind of "packing slip" for a document or collection of documents that are transferred from one company to another. The transmittal might be just the front page in an extensive document. But more often it is a separate document file that contains details of the documents that are sent. The transmittal also contains specific (company or project-related) details to help further processing of the documents for the recipient.
The content of the transmittal document depends on the situation. Some typical content in a transmittal can be:
Transmittals are used in engineering and construction companies as a necessary tool in projects where a large number of documents are involved. Several document handling systems have functions for generating transmittal document along with packages of document for transfer.