PDF files are great for protecting the integrity of a document, but they can be a hassle when it comes time to print them. This wikiHow will teach you how to print them. Online PDF Reader, Online reader, free to read hundreds of file formats online, no need to install, open and use Online PDF URL Or upload a PDF file. More online apps Online document conversion. PDF files are used to send print-ready data to printers. The file format is also frequently used for submitting adverts to publishers or as a graphic file format for logos and drawings.