how to enhance volume on a recorded voice memo

If you really wanted to, you could export the memo to your computer as a MP3 and then use some sort of software like iMovie to increase the volume. Hope this helps!

First, how are you listening to the recording –– speakerphone or the "ear" speaker? (I have to ask, expecting speakerphone volume when it's not activated is the most common reason)

Open the voice memo and pause it. Click the speaker icon in the top right corner to make it colored blue. Turn up your device's volume and play the recording. Hope this helps!