How to Use Keychain

Safari will save usernames and passwords for sites internally. Open Safari preferences then click on the Autofill tab in the toolbar. Check the boxes to sue. The middle one is for usernames and passwords.

It's up to the site itself to register the information from a Keychain entry via cookies used by the site. You should allow this to be done automatically. If you've not logged into the site previously, then when you enter your username and password for the site and click on the Login button a dialog will appear asking if you want to save that information in your Keychain. If no dialog appears then the site does not access the Keychain for that information. Entering the information in your Keychain does not result in the information being filled in automatically unless the site you visit is set up to access the Keychain. You must also have Cookies enabled for it to work in any case.

Only remove the items you entered manually. You don't want to disturb other items in your Keychain since they can affect your system login.

Once done with the above, let Safari handle things for you. Turn on Cookies (Security) but only for sites you visit directly. Check all the Autofill boxes so Safari will save usernames, passwords, etc. If a site has a checkbox to "remember" you be sure you check those when you complete the username and password fields. Don't press RETURN after your entry. Use the site's Login button. If the site uses the Keychain then you will get the dialog asking if you want to save the information in your Keychain. The autofill, however, is handled by Safari itself.

You can use a keychain to store personal usernames, passwords, account numbers, etc. if you wish. You can create new keychains specifically for that purpose and provide unique passwords to access these keychains. The keychains are simply password protected and encrypted data files you can use to keep your personal information secure.

Here's a helpful link.