You can do your own thing since there aren’t “rules” for formatting chapter numbers and titles, but I advocate a conservative approach rather than going all flashbang with it. Your story is your star attraction, not your chapter titles. Use the same font as the rest of the manuscript to avoid distracting from the story, and set them at the top of a new page to echo the reading experience of a bound book. They’re most commonly centered, but flush left is comfortable. You can bold them for a tad bit of drama in breaking from one episode to the next without being too flashy. One line space before and after is the most common line-spacing treatment. Ultimately, let clarity and the natural flow of the entire manuscript be your guide.