Your device can securely store your saved account information such as your passwords and associated user names or email addresses. When you are prompted to enter your account information, such as in an app or within a website, your device may automatically help you enter your information. Your account information is encrypted on your device, and cannot be viewed by Apple.
Your device may suggest actions for you to take to improve the strength of your passwords. For example, your device may inform you that a saved password is weak, is reused across multiple accounts or is a commonly used password. These suggestions are based solely on processing that occurs on your device.
Your device may also inform you of passwords that may have been compromised in a data breach. This feature uses strong cryptographic techniques to regularly check derivations of your passwords against a list of breached passwords in a secure and private way that doesn’t reveal to Apple your accounts or passwords. Apple will send to your device a list of common passwords that are present in data breaches. For your passwords that are not in this list, your device will send information calculated from your passwords to Apple to check if the passwords may be present in a data breach. You will be warned about your passwords determined to possibly be in a data breach. Your actual passwords are never shared with Apple, and Apple does not store the information calculated from your passwords. You can disable this feature at any time by going to Settings > Passwords > Security Recommendations.