On an iPhone with an Action button, go to Settings > Action Button and choose Voice Memo, or choose Shortcut and select Spitball's capture shortcut, then press and hold to record. Which iPhones have the button, both setups, and fixes when nothing happens.
Save a song idea on iPhone the moment it arrives: hum the melody, sing the hook or say the lyric line into Voice Memos or a quick-capture app. Use Voice Memos for full and layered takes, say lyric lines out loud so they're searchable, and name every idea.
You can take voice notes on iPhone with Voice Memos, inside Apple Notes, with the Action button, or in a capture app like Spitball. Here's how each works, what gets transcribed, where the audio is stored, and which one to choose.