Unfortunately, there's no way to change the font/typeface that you are using. There might be a way to do it with the HTML editor, but you run into accessibility issues. With that said, using the Rich Content Editor (https://community.canvaslms.com/docs/DOC-10728-67952720342), you can change the style of your text. You have your standard bold, italics, underline as well as alignment and header options.
If you've got any questions, let me know!