Like other browsers, Safari has a built-in password manager that can autofill website usernames and passwords for you. Here's how to see, edit, and add saved passwords in Safari on the Mac.  When you log into sites or create a new login, Safari will ask you if you want to save the username password.

View and Edit Your Stored Passwords in Safari on the mac:

1.  Go to Preferences in the Safari menu.

2.  Click the Passwords tab. Safari will show you the sites it has saved your logins for.

•  To copy the URL, username, or password, right-click on the login.
• To show the password for an individual login, double-click the password field.  You will be prompted to enter your computer username and password.
• To delete a login, select it and click the remove button.
• To add a new login, click the "add" button and then enter the URL, username, and password.