Backup iPhone 11 using iTunes
When backuping using iTunes encrypted backup passwords are included.
How does this work using iCloud backup?
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What does iCloud back up?
https://support.apple.com/en-us/HT207428
About backups for iPhone, iPad, and iPod touch
https://support.apple.com/en-ie/HT204136
iCloud Backup is by default encrypted, it stores locally saved passwords. If you use iCloud Keychain then your passwords are already stored in iCloud. If you use other passwords manager from other developer, then you need to check with the app developer where passwords are backed up to.