How can I remove/uninstall the Voice Memos app from Mojave?
You can delete VoiceMemos.app from macOS Recovery however, it may/will be replaced during updates/upgrades which contain the deleted app.
- Note: You do not need to disable SIP in order to do this from macOS Recovery.
Boot to macOS Recovery pressing ⌘R when starting the computer. - See About macOS Recovery for additional information.
Turn on your Mac and immediately press and hold Command (⌘)-R or one of the other macOS Recovery key combinations on your keyboard. Continue holding until you see the Apple logo or a spinning globe. Startup is complete when you see the utilities window:
Once the macOS Utilities window appears, open Terminal from the Utilities menu.
In Terminal, use the following example command to delete the VoiceMemos.app.
rm -rf /Volumes/Macintosh\ HD/Applications/VoiceMemos.app
That's it... it's gone... reboot the Mac.
To quit macOS Recovery, choose Restart or Shut Down from the Apple () menu. If you want to choose a different startup disk before quitting, choose Startup Disk from the Apple menu.
Note that this was tested under macOS Mojave and worked as stated.
You can't, officially
Let me explain'
Apple has this thing called SIP or System Integrity Protection. It prevents most people from doing things to their computer that would make it unusable or disable built-in functionality.
Pretty much any app that comes with macOS can't be deleted, unless you disable SIP. Even then if you do disable SIP (It's not hard a quick search will turn up lots of instructions to do so) the next time Apple updates macOS it is likely to return.
Generally disabling SIP is not a great idea as, among other things, it can protect against certain types of malware that try to modify core system files and resources.
So, if you want to, that app can be deleted. But you will have to disable SIP first, and me, I wouldn't do it. But it's your Mac do what you want.