When choosing applications, if using or migrating your data between applications is important to you, look for one or more of these features:
- Drag-and-drop
- Export functions, especially to PDF or text formats like rich text or Markdown
- File Provider support, e.g., access via Files.app, on mobile
- AppleScript support on the Mac, Shortcut support on mobile
But be aware, some applications implement proprietary variations of commonly used functions, like their own flavor of Markdown. Or perhaps they store document metadata in a particular way or location, making it difficult (or impossible) for other application’s to use it. These things may be overcome using other tools, like scripting, but there’s no guarantee it can be done. Apps using standards lead to more opportunities.