OptionalalignOptionalbackgroundWhether the text sits on a filled plate. The other answer to a busy photo: an edge keeps the glyphs readable, a plate takes the photo out from behind them entirely.
OptionalboldHeavier glyphs. Absent on annotations made before it existed, which read as off
OptionalfontWhich family the text is drawn in, the default sans when absent
OptionalitalicSlanted glyphs
OptionaloutlineWhether the glyphs carry a contrasting edge, so a caption stays readable wherever it lands on the photo. Absent on annotations made before it existed, which read as off.
Clockwise degrees around the anchor
OptionalstrikethroughA line through the glyphs
Text content, or the emoji character for stickers
OptionalunderlineA line under the glyphs
How the lines sit against each other. Only has an effect on text that spans more than one line, since the block is exactly as wide as its longest one.