Name sigils apply to names or to the individual person who you had in mind while making a sigil off/from the individual person’s name?
Name sigils are sigils that are used to represent a name, and whatever construct, or entity possesses that name.
Incidentally, what is the use and purpose of said sigils?
These sigils are constructed to represent names of specific constructs, or entities, and can be used to connect with them, summon them, and/or represent them in your magickal working. These sigils can be used as taglocks, because of the magickal link they have between the target, and the sigil. They have also been used in order to make personal magickal seals, and signatures to show ownership, and represent the practitioner that uses them.
And what is the origin and history of said sigils?
These forms of sigil originally came from chaos magick like most sigil understandings, and was probably formed from a new way of thought surrounding the understanding of ceremonial magick sigils for angels, and demons, but I’m not exactly sure on the origins.