Oh, yeah. Do you see at the top of the box you're typing in, the toolbar with Bold, Italic, Underline, and all that?
Just about in the middle of the bar is a chain-link looking thing. If you click that, you can paste a URL into the box, and it will appear as a link. Or, you can highlight words, and then click the chainlink, and paste that URL in, and the words you highlighted will be a link to that URL.