A MIME mail is just an extension of the RFC 822 based email. It however has its own set of RFCs. Header Fields MIME headers are broadly classified as MIME Message Headers and MIME Part Headers, based on their placement in an email packet. The value to be used is 1.0. This identifies the type of data so that it can be handled suitably.
Valid types are text, image, audio, video, applications, multipart and message.
It can take one of 7bit, 8bit, binary, quoted-printable, base64 and custom, per attachment. 8bit and binary encoding are not used in general. Quoted printable is used for human-readable normal text if it has to be protected in transit through a gateway that will affect the formatting. This is outside the scope of this article. Free text descriptions of the contents of any message part.