PictureAdded by pasting from the clipboard or using the box at the top right. Click and drag to place. Click and drag with the shift key inside to scale. Double-click to center.
TextClick and drag with the Option key inside to place the heading freely. Can reset using the location selection on the right.
Use *text* to bold or _text_ for italic similar to how it works on Slack. And, use [[text]] to highlight.