A password manager is like your mommy's recipe book, but for your usernames and passwords! Just like your mommy writes down all her favorite recipes so she doesn't forget them, you can use a password manager to remember all your different usernames and passwords for different websites.
Every time you create a new username and password to sign up for a website, you can ask your password manager to save it for you. Then, the next time you come back to that website, you don't have to remember your username and password – your password manager will do it for you!
It's important to use a password manager because you should never use the same password for different websites. If someone hacks into one website and gets your password, they could use that password to access all your other accounts too. But with a password manager, you can use different, strong passwords for every website, and your password manager will keep them safe and secure for you!