Subscribe to our newsletter. Pressing the 'Send' button is like handing your letter to the postman that comes to your house. The same happens with your email message. Your email program sends the message to the nearest email server.
Email servers are the post offices of the Internet.
The program will have a look at the recipient's email address. Then, it sends the message on to the email server nearest to the recipient. There, another postman will pick the letter up and deliver it to the recipient. It connects to the email server and fetches the latest messages from there. Then they are presented to the recipient, and to whoever you sent your email can read it on their screen.