Basically, put what genre this character is from, and then a description of them/ introduction to their character. Try to make them as typical a main character for that genre as you can. You can also include stuff that's true but wouldn't typically be included in a book (like how bad your character is at making descisions). Self aware characters are great!
For Example, this is my attempt at a YA dystopian/romance heroine:
My name is Lena, short for Magdelana. I'm ordinary, but pretty, with bright blue eyes. I love art, music, and reading. I also have a great, but slightly weird, fashion sense. I have a unique ability that only 5% of the population has, but I hate my powers. I want to be normal. I absolutely love my parents and sibling, but I don't always agree with them. I'm just different. I'm also super athletic, even though I never excercise and rarely spend time outside, though I do love nature. People always underestimate me because I'm a girl, but I'm the best, and can do anything I want without any consequences or problems. I'm also not very good at social interactions, but we all ignore that and pretend it's everyone else's fault when I fight with them.
There you go! Can't wait to see what everyone comes up with. Hope I put it in the right forum thingy.