There's always a new app that promises to make you more productive. When it comes to note taking and writing in general, I think I've tried dozens of them over the years. No more, I'm done wasting time.
My favorite app, by far, is the default Notes app on iOS / Mac OS. It's basic, and I love that. It does what's supposed to do, and no more. It synchronizes across all my devices, so I can script a video on my computer, draw something in that same note on my iPad, and add new ideas from my phone during my walks.
It's also free.
Productivity isn't about finding a new app / trick / life hack. It's about using what we already have, right in front of us.