Hey there little one! Do you know what email is? It's like sending a letter to your friend through the computer! And in order to send and receive those emails, your computer and the computer of your friend need to talk to each other. That's where Simple Mail Access Protocol (or SMTP) comes in.
SMTP is like a special language that computers use to talk to each other about email. It helps the sender computer understand where to send the email, and it helps the receiver computer understand how to receive it. Kinda like telling your friend your home address so they know where to send the letter, and giving them instructions on how to open your mailbox to get the letter!
For example, imagine you want to send an email to your friend named Sarah. First, your computer will use SMTP to talk to a server that belongs to your email provider (like Gmail). It will say "Hey! I want to send an email to Sarah!" and share the email's content. The email provider's server then uses SMTP to talk to a server that belongs to Sarah's email provider. It will say "Hey, I have an email for Sarah from her friend!" and share the email's content.
Finally, when the email arrives at Sarah's email provider's server, her computer will use Simple Mail Transfer Protocol (or POP3) to download it from the server and show it to her. Just like how you might open the mailbox to collect your letter!
So that's how SMTP works - like a special language that computers use to talk to each other about email, helping them send and receive emails easily!