Amazon Studios is the part of the company that is producing original series and movies. They have just unveiled a new free tool that writers of novels or scripts will find useful. It's called Amazon Storybuilder, and it's a virtual corkboard that you can access from your computer, phone, or tablet.
Many writers use index cards with one phrase or sentence per scene or story beat. It's easy to move them around and add or subtract them as you develop the story. I do the same thing with sticky notes on a whiteboard. On Storybuilder you can have up to 1000 cards per project, many more than you'll ever need. On a typical feature film or TV movie, I seldom use more than 100.
The advantage of something like Storybuilder (similar apps are available) is that you can access the virtual cards wherever you are--as long as you have a wifi signal, that is. The cards live in the cloud, not on your device.
Your cards are private unless you invite someone (e.g., a collaborator) to have access to them.
Since I'm going to be travelling quite a bit in the next few months I'm going to give Storybuilder a try. If you want to as well, go here (you may need to sign in to Amazon first): https://studios.amazon.com/storybuilder
(Do you want friendly, practical guidance in writing your book or screenplay? You'll find it in my book, Your Writing Coach, published by Nicholas Brealey and available from Amazon or your other favorite bookseller.)