To password protect a PDF in Adobe Acrobat Reader, you'll need the paid Pro version, which starts at $14.99 a month.

You can edit a PDF on your Mac with Preview, an app that's built-in to your computer from the start. You can use this program ...

WhatsApp can do more than send messages and photos. A hidden tool inside the app turns stacks of paper into tidy digital files in just a few taps.

I don’t use Microsoft Excel all that often, so it remains a bit of a mystery to me. I can enter text and create graphs and that’s basically it. That’s why I’ve set myself a goal to learn one new Excel ...