Formerly Talk to Think.
Say it messy. Send it clear. Nothing leaves your phone.
Live words take a moment to appear. Your iPhone listens for a few seconds before the first words show, then keeps pace as you talk.
It misheard a word. Tap the sentence, tap the pencil, fix the word. The app remembers, and fixes that word by itself next time. You can see and remove what it learned in Settings.
Sending to Notes. Press Send, then Share, then pick Notes.