Instead of highlighting the link and copying it as Snakeyes suggested, I prefer to right click on the link and select Copy Shortcut. Then you can paste it into the email as Snakeyes suggested.
Another way to paste is to press the Ctrl key and the V key at the same time. This will paste whatever is in the Clipboard (in other words, what you have previously copied) to where the cursor is. To copy using only keys, press the Ctrl key and the C key at the same time.
To make something else clear, left click means to press the left button on the mouse (this is the button that is usually used to click on things). Right click means to press the right button on the mouse.