Read/watch these support items -->
Read this support article to discover how to restore your iPhone, iPad, or iPod touch from a backup --> Restore your iPhone, iPad, or iPod touch from a backup - Apple Support
This support article has instructions on how to restore an iPhone or iPad from an iCloud backup -->
Restore your iPhone, iPad, or iPod touch from a backup - Apple Support
or watch this video if you're using a Mac to do this:
https://www.youtube.com/watch/Jbp3gGTQygg
Related information:
Use iCloud to transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch --> Use iCloud to transfer data from your previous iOS or iPadOS device to your new iPhone, iPad, or iPod touch - Apple Support
Some things are not stored in a backup. Click on this link and read "About missing information after you restore your iOS device with iCloud Backup" -->
About missing information after you restore your iPhone, iPad, or iPod touch with iCloud Backup - Apple Support
If you can't back up your iOS or iPadOS device to a computer or restore it from a backup --> If you can't back up your iOS or iPadOS device to a computer or restore it from a backup - Apple Support
Which iCloud.com features are available in the browser on your device --> Which iCloud.com features are available in the browser on your device - Apple Support