Voice memos that were recorded in Apple's native Voice Memos app on an iPhone or iPod Touch are located in the Media Library section of iExplorer and transfer just like music tracks. You'll see the Voice Memos category listed under Media Library. If you don't see it under Media Library, click on the disclosure triangle next to it. Then, just click on Voice Memos in the left panel to view the list of them in the main window and use the export options to transfer any to your computer.
If you have any issues in Media Library or you don't see all of your voice memos, try going into Media folder/Recordings which is where the actual voice memo .m4a files are stored, and you can drag/drop any of those to your computer or right-click one and choose Export to folder. Hold Control (PC) or Command (Mac) to select more than one.
If you have an iPad, Apple's native Voice Memos app isn't available or included with iOS for iPad like it is on an iPhone or iPod Touch, so if you have voice memos on an iPad, they must have been recorded with a 3rd party app that was downloaded from the App Store, and any data from those apps will be in the Apps section or in the Backup Explorer section of iExplorer depending on where the app stores the audio files for the memos and whether the app has iTunes File Sharing enabled or not. The article below explains more:
The Apps section isn't showing all of my app folders. Why is that?