Using app-specific passwords
App-specific passwords allow you to sign in to your account securely when you use third-party apps with your Apple ID.
App-specific passwords are single-use passwords for your Apple ID that let you sign in to your account and securely access the information you store in iCloud from a third-party app. For example, use app-specific passwords with Microsoft Outlook, Mozilla Thunderbird, or other mail, contacts, and calendar services not provided by Apple. App-specific passwords maintain a high level of security and help ensure your Apple ID password won’t be collected or stored by any third-party apps you use.
To generate and use app-specific passwords, your Apple ID must be protected with two-factor authentication.
Generate an app-specific password
Sign in to your Apple ID account page.
In the Security section, click Generate Password below App-Specific Passwords.
Follow the steps on your screen.
After you generate your app-specific password, enter or paste it into the password field of the app as you would normally.
Manage app-specific passwords
You can have up to 25 active app-specific passwords at any given time. If you need to, you can revoke passwords individually or all at once.
Sign in to your Apple ID account page.
In the Security section, click Edit.
In the App Specific Passwords section, click View History.
Click next to a password you want to delete, or Revoke All.
After you revoke a password, the app using that password will be signed out of your account until you generate a new password and sign in again.
Any time you change or reset your primary Apple ID password, all of your app-specific passwords are revoked automatically to protect the security of your account. You'll need to generate new app-specific passwords for any apps that you want to continue using.