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The purpose of RFC 822 is to revise the standards that had previously been codified, culminating in RFC 733. The document's scope is the syntax of electronic-mail text messages. Messages contain two major parts, envelope and contents (see About Simple Internet (RFC 822) Messages), though the envelope is specifically not described in the document.
In a forward-looking way, RFC 822 states that, although its specifications are intended for use on the ARPA Internet, "an attempt has been made to free it of any dependence on that environment, so that it can be applied to other network text message systems."
Also, RFC 822 defines only what information is passed between Internet hosts, not how messaging systems are used to store, create, or read messages or the information they contain.
Messages consist of "lines of text," with no special provisions made for encoding drawings, facsimile, speech, or structured text. Little consideration is given to questions of data compression or to transmission and storage efficiency.
The RFC 822 message will use a general "memo" framework in which initial information is presented in a rigid, defined format (the headers section) followed by the main part of the message whose format is unspecified.
The described framework has limitations, specifically that its constraints on document tone and appearance make messages of this format "primarily useful for most intra-organization communications and well-structured inter-organization communication, as well as for some types of inter-process communication, such as simple file transfer and remote job entry."
It is speculated that "a more robust framework might allow for multi-font, multi-color, multidimensional encoding of information," whereas "a less robust one, as is present in most single-machine message systems, would more severely constrain the ability to add fields and the decision to include specific fields."