PDF files allow you to view books, forms, manuals and other documents as the author originally intended. These documents were originally developed for use on personal computers, but you can also download PDF files directly onto your iPhone for portable convenience. Using a compatible PDF viewer, you can read your favorite e-books on the go or store important files in your pocket.
Launch the App store from the iPhone's home screen. Tap "Search" and type "PDF" in the Search field. Download any of the best-rated apps that support PDF files -- those with four or five stars. Some of the most popular apps include Adobe Reader, Apple iBooks and Noteshelf - Notes & PDF.
Open the "Safari" app, usually appearing along the bottom row of your home screen, and locate a PDF file online. Alternatively, email a PDF file to your iPhone from a computer.
Tap the PDF file in Safari or your email message. An Open button appears on the screen inviting you to open the PDF in your PDF viewer, such as "Open in iBooks." Tap the button. The PDF is automatically saved in your PDF viewer app.