It depends on the type of printer you have. If you have an HP ePrinter, HP has an app that allows you to print from your phone. If you have an HP all-in-one, there is another app that allows you to scan directly into your phone. I believe the other manufacturers have similar apps if you have a web enabled printer.
If you sign your printer up for Google Cloud Print, there is a Cloud Print app.
There are some limitations as to the type of files you can print from these apps, but both will handle most file types you have on your phone. I find that the Cloud Print app will handle more file types, but some times it takes a while for the Google Server to send the information to the printer. I believe the Cloud Print app also has the capability to save the printout as a PDF.