You can delete individual recordings or multiple recordings at the same time
To delete a single voice recording:
Tap Apps.
Tap Recorder.
Tap the Menu icon.
Select the recording you want to delete.
Tap the Bin icon.
Tap Delete.
To delete many voice recordings:
Tap Apps.
Tap Recorder.
Tap the Menu icon.
Tap the Pencil (Edit) icon.
Select the check boxes next to the recordings you want to delete.
Tap Delete.
Tap Delete again to confirm.