SAML 2.0 is like a secret handshake between your computer and a website. When you want to log into a website, you have to prove that you are who you say you are. So, you tell the website your name and password, and the website checks to make sure it's correct.
But sometimes, you might be logging into lots of different websites. And you don't want to have to remember all of your different passwords. That's where SAML 2.0 comes in!
SAML 2.0 lets you use just one password to log into lots of different websites. How does it do this? Well, the website you're logging into doesn't actually check your password. Instead, it asks a special "middleman" called an identity provider to check your password for you.
So, instead of lots of websites checking your password themselves, they all ask the identity provider to do it. And the identity provider knows that if you've already logged in once, you must be who you say you are. So it sends a signal to the websites telling them that you're allowed to log in.
And that's how SAML 2.0 lets you use one password to log into lots of different websites - it's like having a secret password keeper that only you and the websites you use can access!