I assume you are using Super Voice Recorder from MeiHillMan.
He has mentioned the storage location of your files in
Play Store Page
Audio recording files are stored into “AllVoiceRecords” in your SD card root folder. In addition to using the built-in player, you can use your device’s file browser or a USB PC connection to view, copy or share the files in the directory.
All recording files are placed under the directory "AllVoiceRecords" (this directory is at the root of SD Card). Apart from viewing or playing in this application, you can also manually view or copy those records using a file browser, or transfer them to your PC through USB connection.
On Windows, if you can't see your files from Explorer, and you're familiar with ADB, open CMD shell and try this command:
adb pull /sdcard/AllVoiceRecords %userprofile%\desktop
You'll find a folder called AllVoiceRecords on your desktop.
Otherwise, if you want to view your files via Windows Explorer, try media.Re.Scan application to scan your MTP media storage and update its information.