Set up iCloud Keychain to autofill information on Mac
iCloud Keychain keeps the website login information and credit card information that you use with autofill in Safari, and your Wi-Fi network information up to date across all your Mac computers (OS X 10.9 or later), iOS devices (iOS 7.0.3 or later), and iPadOS devices.
iCloud Keychain also stores account settings, so your social media accounts can be added automatically to another Mac when you sign in with your Apple ID on that Mac. For example, Exchange, Google, and other internet accounts you use with Mail, Contacts, Calendar, Reminders, Notes, and Messages can be added automatically.
Everything stored in iCloud Keychain is secure—it’s protected by industry-standard encryption. Your iCloud Keychain can’t be set up on another Mac or iOS or iPadOS device unless you approve it.
Set up iCloud Keychain on your Mac
On your Mac, choose Apple menu > System Settings, then click [your name] at the top of the sidebar.
If you don’t see your name, click “Sign in with your Apple ID,” enter your Apple ID (or a Reachable At email address or phone number that you added in Apple ID settings), then enter your password. If you don’t have an Apple ID, you can create one.
Click iCloud on the right, click Passwords & Keychain, then turn on Sync this Mac.
Follow the onscreen instructions to set up two-factor authentication if you haven’t already.
You must also set up your Mac to require a login password before you can use iCloud Keychain.
Approve a new device to use iCloud Keychain
If you use two-factor authentication and have already set up iCloud Keychain on another device, you can easily approve a new device to use your iCloud data. On the new device, when prompted, enter the login password or passcode of a device that already has iCloud Keychain set up.
Removing credit card information or account names and passwords in Safari (or with Keychain Access) deletes them from your macOS keychain and from your iCloud Keychain.