My Voice Memo app on iPhone 7s v.12.4.1 is not letting me change/edit the titles on any of my voice memos since the upgrade.

Good afternoon shadowdog3,

Welcome to the Apple Support Communities!

I understand you are having issues renaming files in the Voice Memos app on your iPhone 7. Did this issue happen before or after the update to iOS 12.4.1.

I use the Voice Memos app quite a bit, and am not having any issues changing the file name. I'm not sure what steps you have already tried but this is what I suggest:

1. Quit the Voice Memos app on your iPhone
2. Turn off the iPhone
3. Restart the iPhone
4. Create a new Voice Memo
5. Tap on the temporary file name - (ex. New Recording ##) - the entire file name should have a blue background if it is selected.
6. Start typing a new name for this file (ie. Test)
7. Tap the Return key on the onboard keyboard when you are done typing
8. The file should remain at the top of the list, as they are shown in chronological order with the most recent recording on top.

iPhone User Guide - Make a recording in Voice Memos on iPhone

If the issue persists, you may need to reinstall the iOS. The process below will not remove the existing data on the iPhone, but you should always have a backup before making changes like this.

How to back up your iPhone, iPad, and iPod touch

If you can't update or restore your iPhone, iPad, or iPod touch -- follow the steps in the "Put your device in recovery mode" section and be sure to choose "Update" in step #4.

Take care.