With the evolution of computer networks such as Bitnet and the Internet, email has grown exponentially in scope and use. Today Electronic mail is used to communicate with vastly more people than was originally envisioned, each with unique uses of this medium. Years ago, savvy people recognized this and started using email to send more than simply text memos to other users. Accordingly, they can not simply be placed in an email message in the same manner as one would enter the text of the note. Their unique structure necessitates converting the file so that it may be included in the email message.
Encoding is a systematic means of changing a binary file to a text file of some sort.
Most other desktop based email programs offer encoding of some type. In theory, the process is relatively simple. Different email programs utilize different formats. Therein lies the crux of the problem. It is used heavily with web browsers.