I love using Mind Maps Pro to create the key elements for my stories or characters.

You can brainstorm the elements out graphically and easily move them around and expand any element out as much as you want.

Now you have the “BONES”, as I like to call them, for your story or one of your characters and you can proceed to add the “FLESH” to the bones (elements).

Below are some examples of how you can use this tool for writing:

Story Development

Character Development

I have only used the Windows version which can be purchased from the Microsoft Store at: https://apps.microsoft.com/detail/9mwz4wtswwp5?amp%3Bgl=US&hl=en-us&gl=US. I do not see an iOS version.

Here are two similar types of Mind Map applications on iOS systems which have good reviews, but I have not personally used them: https://apps.apple.com/us/app/mindnode-mind-map-outline/id1218718027 or https://apps.apple.com/us/app/simplemind-pro-mind-mapping/id378174507