There are many great multi-platform writing apps out there that are not Google Docs or Evernote. Here are a few that I've used or heard good things about:
• Microsoft Word – Microsoft Word is a great word processing alternative to Google Docs and Evernote. Word documents can be accessed from nearly any platform, including Windows, macOS, and mobile devices.
• Ulysses – Ulysses is a polished, distraction-free writing app for Mac and iOS with great organizational tools. It supports Markdown, which makes formatting text a snap.
• Notion – Notion is a powerful digital workspace that’s great for writing and organizing notes. It has a ton of useful features and is available on Windows, Mac, iOS, and Android.
• Quip – Quip is a collaborative markup editor for real-time collaboration. It’s great for writers who need feedback or are working on a team-based document.
• Bear – Bear is a versatile note-taking app available on iOS and Mac. It has an intuitive design and is straightforward to use.
• iA writer – iA Writer is a great app for short-form writing and blogging. It has a clean and distraction-free interface and is available on Windows, Mac, and mobile devices.
Whichever app you choose, make sure to do some research and read up on its features and capabilities, so you can decide if it's the right choice for you and your writing needs.