This infographic gives brief summaries of the 12 Jungian personality archetypes, for use when building charcaters. As with any writing tools, archetypes are really most useful if you think of them as a starying block - you cannot simply reduce people to 12 options. Most people will show traits from multiple categories. As a writer, you may want to think about each character's primary and secondary archetypes. As always, remember: Tools, not rules!
In the Harry Potter universe, there's not really any need to text. People can use floo powder to talk to other wizards and witches through their fireplace and they can apparate at will. But what might happen if the characters from the Harry Potter books started texting one another?