Name: Hopefully not too complicated. There
is, however, a good
list of names in Fates provided for generic units that should give you a good idea of what sort of names are common where.
Age: Try not to give a 2015-era Reddit answer of, "She looks 8 but ackshually she is 5000 years old" and pretend it's comedy gold.
Nationality: The character's nation of identification, usually also their country of origin. Exceptions exist, though, and if that's the case, a denomination marking such (EX/ "Sagessian, Nationalized Nohrian") will be nice.
Class: As this is mostly something used for equipment and familiarity, you can flavor this however you like. Don't expect me to kiss your ass because of whatever you put here. You can find a list of classes
here.Role: Your character's position in the Company. Check in the "Roles" tab for more info.
Appearance: Pilfer some anime-looking goofball from Google or DeviantArt and plaster their pretty mug here. If you feel ambitious, draw them yourself. Either way, a brief (one paragraph or so) description of their appearance - what they wear and how they look - will do.
Personality: I don't expect text walls here - just write down the gist of what they're like as a person so that nobody's surprised when pen hits paper.
History: Write as much as you think is necessary. A few paragraphs are fine, but don't feel like you have to kill yourself over this. You can always add on more In-Character.
Skills: No, not
those skills. Basically, list out what your character is good at.
Trivia: Anything you think that needs saying but doesn't fit anywhere else goes here.