Many software products like the Microsoft Office applications provide the option to save your document, spreadsheet, etc. as a PDF.
However, if that option isn’t available within a program you are using but there is the option to “Print,” you are half-way there. If you haven’t already done so, you will need to install “PDF Printer” such as Adobe, FoxIt, cutepdf, BullZip, etc. Once installed, you wouldn’t have to print any document on paper! Instead, you will be able to select the applicable “PDF Printer” from your printer list. The print process generates a PDF and provides you with a “Save As” option.