How an email works

First of all, you, the sender composes a message using a web based or client based email software. The most familiar web based softwares are known as hotmail, yahoo and gmail.
then the sender types the address it would like the message to go to. The message is then sent to the senders ISP's mail server where it chooses the best route for it to get to the recipients address that was previously typed in.
The email is then sent throught the interent and arrives at the recipients ISP's mail server and is stored until the email is seen.

Here is a flow chart.