Well, it depends on where the bio is for me, really. If I'm using the in-game bio, I try to put only the necessities plus a little snippet of what the character is like so people can get an idea of their personality. I try not to put too much, but enough so that they get an idea of who they are going to be roleplaying with. If the character is apart of a group and has a rank, then I put that in with all the other information as well,
If the bio is placed somewhere like a forum of sorts, then I go all out of what the character is about, what they've been through, family trees, backstory, and all that stuff. Really just to have the character lined out for myself and anyone else who really likes the character and wants to get to know them more. There I also like to put miscellaneous details down on favorite things, food, activities, and even other characters they have met and how they feel about them- be it inside their group or outside. Almost like notes to myself xD but, mainly to document their journey and everything they've been through.
For both, I like to have a combination of my own template and just describing the character. I feel like it keeps things organized and easy to find.
For the big words and stuff, personally, I don't like using those big Latin words and whatnot. To me it just confuses things, but that's just my preference. I usually don't like being flashy about it (unless I'm decorating it, muhaha).