This MacWorld article is an excellent summary of all the ways to trigger the shutter remotely in your iPhone’s camera app.

• MacWorld > “How to remotely control your iPhone’s camera” by Lance Whitney (May 13, 2021) – Take a photo without touching your phone.

(quote) There are several reasons why you might not want to hold your iPhone while taking a picture: You need to snap the perfect still photo while your iPhone is on a tripod and don’t want to spoil the shot by jostling it. You’re taking a group photo but also want to be in it. You’re too lazy to lift your finger. …

• Apple watch’s camera app
• Voice control (Accessibility)
• Siri
• Bluetooth camera shutter remote