How to use the Safari browser’s automatic creation of strong password function to protect password security?

In the Safari browser App on Mac:

When you start to create a new website password, if you have already set up the iCloud keychain on your Mac, the system will suggest a unique and difficult-to-guess password for you. If you haven't set up an iCloud keychain, click the password field, click "Auto-fill key", and then choose "Suggest a new password."