Gmail is one of the most popular email clients in the world and it has some very useful features. One of the most useful features of Gmail is the ability to send someone a copy of an email that you send. This is a very useful feature for many reasons. One of the most popular reasons for sending someone a copy of an email that you send is because you want them to be a part of the entire email chain. If you are sending an email to a customer, it is a good idea to have them a part of the entire email chain so they know what is going on. To CC someone on a Gmail email, you simply have to click the Cc button in Gmail while you are writing your email.