A friend asked me why on earth I'd need a PDF app on my phone. Rather than explain briefly, I made a 40 minute video. Here is my soup to nuts explanation of how I use PDFpen for iPhone.
If you haven't bought the app yet, you should right now. Smile just dropped the price (for a limited time) on PDFpen for iPhone* to $2. (PDFpen for iPad* is also on sale for just $7.) Watch the video, buy the apps, tell your friends. You can't go wrong.
* Affiliate link lining my pockets one nickel at a time.