Missive implies "written communication." It is often a written letter addressed to an individual or an organization. An opinion expressed by a reader in the written language and sent to a tabloid to be published is called as a "missive." The first time the word was used in popular English literature was in the year 1350. The popular synonyms of the word "missive" are letter, memo, epistle and note.
A missive was thought to be something which is "on paper." However with the influx of the internet, letters or missives can be sent through email too. So in other words, a missive can be in the form of a soft copy too. A missive or a letter is always assumed to be more credible from the point of proof or evidence rather than the "spoken word," which even if recorded, can be claimed as doctored. A hand-written missive cannot be claimed to be doctored because there are handwriting analysts who can trace out the writing to the person who actually wrote it.
A missive was thought to be something which is "on paper." However with the influx of the internet, letters or missives can be sent through email too. So in other words, a missive can be in the form of a soft copy too. A missive or a letter is always assumed to be more credible from the point of proof or evidence rather than the "spoken word," which even if recorded, can be claimed as doctored. A hand-written missive cannot be claimed to be doctored because there are handwriting analysts who can trace out the writing to the person who actually wrote it.