Various hypotheses have been put forward as to why and for what purposes the Voynich Manuscript was created. To some extent this is made more difficult by the absence of other texts using the same 'script' and a lack of other context (where it actually originated and who was involved in its creation etc).
The costs of the materials (vellum, inks and colours), the length of the manuscript (a number of pages having been lost), and the time required to actually make it (design/layout, drafts of the text and images, acquiring an ease in writing the script, and then creating the actual manuscript) have to be considered in analyzing its possible purposes.
Given the length and arrangement of the text and images, and the relatively few corrections there would have had to be some draft/layout versions and practice texts - but these have not survived/been found (despite having had to exist in some numbers).
- The VM is a hoax - possibly of the time the vellum was made (first part of the 15th century) or a more recent construct - however analysis has shown that the text probably dates to the time of the vellum.
- It uses a constructed language, cipher or codes, steganography, or is in an exotic natural language or hybrid language.
- It is a form of outsider art/glossolalia). The costs argument might well be an argument against this.
- It is a display object (for whatever purposes - whether by a charlatan or other person).
- It is linked to events and views at the time of its creation (in the early 15th century) - eg a purported document from Prester John or similar figure. (This is an example rather than a proposed solution).
- It belongs to an obscure, otherwise unknown group, who have not left any other traces. Given that it is written in a practiced hand it would be surprising that there are no other documents - the persons involved would have to operate in the ordinary world and have left other traces.
- 'Something to do with extraterrestials' and similar possibilities which are presently considered of low probability.
Its functions, especially among earlier owners may have changed over time.