What is Keychain Access on Mac?
You can use Keychain Access to manage certificates, which are issued by trusted organizations to validate websites, digital documents, and other web-based materials.
Tip: You can find all your passwords, passkeys, and verification codes in the Passwords app 
on your Mac. See the Passwords User Guide.
Keychain Access works in collaboration with iCloud Keychain, which lets you share keychains with your other Apple devices. To create and manage your iCloud Keychain, sign in to your Apple Account. See the Apple Support article Set up iCloud Keychain.
To open Keychain Access, search for it in Spotlight, then press Return.
Important: To ensure that data stored in your keychain are secure, make sure to set up a login password for your computer. See Change the login password.