Open the Messages app
Open an existing conversation or start a new one
Tap and hold the microphone icon next to the text field
Record your audio message
Release to send the message automatically
Swipe up while recording to lock the recording if needed
Tap the stop button if you want to review before sending
Tap the play button to listen to the recording
Tap the send button to send it
Tap the delete button to discard it
Make sure microphone access is enabled for Messages in Settings