Hello feisty70,
Thank you for using Apple Support Communities. We'd like to help answer your question. If you plan on using iCloud to keep your data safe, you have two options. You can choose to sync your data with iCloud or use iCloud to backup your data. This resource does have more details on how syncing and backing up works: What does iCloud back up? - Apple Support
The resource does mention the following:
If you're using iCloud Photos, iCloud Drive, or Notes, your information automatically syncs to the cloud and is kept up-to-date across all of your devices whenever you make a change.
Any data on your device that isn't regularly synced is stored in your iCloud Backup. With Backup turned on, iCloud takes periodic snapshots of this data to make sure that it's easy to restore any time you get a new device.
If you want to just sync your Voice Memos with iCloud, then follow the steps listed here: Keep recordings up to date in Voice Memos on iPhone - Apple Support
iOS or iPadOS: Go to Settings
> [your name] > iCloud > Show All, then turn on Voice Memos.
We hope this information helps you. Thank you for using Apple Support Communities.