Star and label messages before you send them
Organise your messages as you send them by adding a star or a label, making it easy to keep track of your sent messages.
When composing a new message, you can assign labels or star it by using the labels drop-down menu. Once you do this, your sent mail will be shown in your labels or starred items. It's a very useful feature, allowing you to keep track of sent messages, in the same way as received ones.
Recipients won't see the stars or labels you have added.