If you are writing for an English class project, the best readable font is 16-18 point for the title and 14 point for the body of the project.
Times New Roman is the best to use for most English, Science, and Social Studies projects.
If you are writing a story, a creative piece, or for some other purpose, you could use wordart, but be very careful that it is readable and professional looking. That goes for any other font types that you use as well.
When I present materials for younger kids, I like to use comic sans because it makes your a more like a child's printed a, so it becomes understandable to younger readers.
You could also use that in the middle of a story if you wanted to illustrate the note that a kid wrote.
Try to use the color type to bring out important words instead of the highlight. That can add interest to your writing as well, but don't use it too much.
Simple, dull, readable, standard type is usually the best and most professional.