SYNC DEVICES WITH iCloud
Set up iCloud on all your devices
https://support.apple.com/guide/icloud/set-up-icloud-on-your-devices-mmfc0f1e2a/icloud
To set up iCloud on your devices, sign in to each of them
with the same Apple ID and password. You can choose which
apps store information in iCloud and which iCloud features
you're using separately on each device. Learn more about how
each app or feature uses iCloud.
How to fix iCloud sync in seconds
https://www.computerworld.com/article/2916476/how-to-fix-icloud-sync-in-seconds.html
Here's what to do when your contacts or calendar events
don't sync between devices.
SYNC APPLE DEVICES WITH A COMPUTER
Sync your iPhone, iPad, or iPod using your computer
https://support.apple.com/en-us/HT201253
Use the Finder to sync your iPhone, iPad, or iPod with your
computer
https://support.apple.com/en-us/HT210611
Starting with macOS Catalina, the Finder replaces iTunes as
one of the ways to sync your device with your Mac.
The Finder is a macOS feature for browsing and accessing
content on your computer. If you update to macOS Catalina or
later, you can use the Finder to sync content between your
Mac and your iPhone, iPad, or iPod touch. The experience is
similar to using iTunes.
Use iTunes to sync your iPhone, iPad, or iPod with your
computer
https://support.apple.com/en-us/HT210612
If you're using macOS Mojave or earlier or a Windows PC, use
iTunes to sync content to your devices. Before you use
iTunes to sync content to your iOS or iPadOS device,
consider using iCloud, Apple Music, or similar services to
keep content from your Mac or PC in the cloud. This way, you
can access your music, photos, and more on your devices when
you aren't near your computer. Learn more about using Apple
Music or iCloud Photos instead of iTunes.
sam.wormley@icloud.com