What are webhooks?

Imagine you have a toy mailbox in your room, and sometimes your friends send you letters or small gifts. Normally, you would have to wait by the mailbox and check if there's anything new. But what if the mailbox could let you know as soon as something arrives?
Well, that's kind of how webhooks work. Instead of waiting and checking if something happened on a website or app, webhooks are like special signals that get sent to you automatically whenever something important occurs. It's like the website or app is saying, "Hey, something new happened! Come and see!"
Just like your mailbox needs to know your address to send you things, webhooks need to know where to send the signals. You set up a special address, like your email or phone number, and tell the website or app to send the signals there.
So whenever something happens on Simple Phones, like a new message or call, it sends a signal to your special address. Then you can quickly know that something happened without having to keep checking all the time.