Type / in a note to insert: Text, Heading 1–3, Checklist, Bulleted list, Numbered list, Quote, Divider, Image or file, Sketch, Canvas, Diagram, Table or Code block.
The Insert menu in the toolbar has the same blocks, plus Voice note and Meeting notes.
On a computer, right-click a blank part of a note (an empty line, or the space beside or below the text) to open the / menu right there. Right-clicking text still shows your browser's menu, for spelling, copy and paste.