Pretty much the camera on my IPhone and Craigslist on my IPhone or my Kindle Fire. I tried using OneNote to keep track of what I pay for project machines and what they need but, gave up on it because my hands were always dirty from working on the projects when I remembered I needed to add them to OneNote. Now, I just take notes in a note book using an old fashioned ball point pen. I can easily write messages about folks that have called, what they have to offer or what they need, phone numbers.. Some things are just better the old fashioned way..