An app I use every day is Ulysses for writers. Some writers swear by Scrivener, but I like how easy Ulysses is to organize and create files and how well it syncs through iCloud to all my devices. If I get an idea for an editorial while I’m in the doctor’s waiting room or traveling or running on the treadmill, I can stop and capture the idea in a new file or a file I’ve already created. Ulysses costs $4.99 a month and is only available through the Apple store.