Brackets doesn't have any built-in printing command yet – you'll need to copy/paste into some other app to print code.
You can do this with full color syntax highlighting using my 'Copy as HTML' extension for Brackets. This lets you copy fully colored code and paste it into something like Word for printing (or save it in an HTML file and print using your browser, for that matter).
If you'd like to see a more robust printing feature built into Brackets, please vote for the Print source code feature on the Brackets backlog.