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It's an on-screen toggle button in the Notes app. Press to start recording, take your time, don't worry about about a 10 second turn around if you pause slightly too long between words, just speak and toggle the button back off when you are done. If someone walked up and had a conversation half way through just delete the words.

They could be refering to the "action button" on the newer Pro phones, which replaced the silent switcher.

They might be referring to an on screen button.

Check out the new voice transcription feature in iOS 18. On my SE 2022 (very much not high-end), I have a good-size record/pause button on screen.

After you’re done with the voice recording, it gives you a transcription of what you spoke.