Settings

Open them from the menu bar icon (Settings…) or with ⌘, in the scripts window. Everything changes the prompter as you move it, even while it's showing, so you can set it up mid-rehearsal.

Prompter

Setting	What it does	Default
Placement	Top of screen hangs it from the top edge, under the camera. Floating makes it a card you can drag anywhere.	Top of screen
Display	Which screen it goes on. Automatic is the one with the notch, or the main one if none has a notch.	Automatic
Width	How wide it is, 280 to 1000 points. At the top of the screen it's never narrower than the notch plus a little.	520 pt
Height	How tall the text part is, 60 to 420 points.	150 pt
Text size	14 to 64 points.	24 pt
Line spacing	1.0 to 1.8 times the line height.	1.2×
Text color	Any colour. Cues and notes are drawn in a dimmer shade of it.	White
Alignment	Left or Center.	Left
Mirror	Flips it left to right, for reading off a teleprompter's glass.	Off

Voice

Setting	What it does	Default
Mode	Follow, Voice or Steady. Follow, Voice and Steady explains them.	Follow
Speed	How fast Voice and Steady scroll, 4 to 120 points a second. ⌃⌥= and ⌃⌥− change it from anywhere.	12 pt/s
Mic sensitivity	How quiet still counts as talking, for Voice and for the dot. Higher hears softer speech.	0.50
Language	The language Follow listens for. Automatic is your Mac's.	Automatic
Pause on hover	Whether pointing at the prompter pauses it.	On

Shortcuts

The list of shortcuts, as in Shortcuts and the menu bar.

Where they're kept

In ~/Library/Preferences/xyz.tiresia.prompter.plist. To start over with the defaults, quit Prompter and run defaults delete xyz.tiresia.prompter.