Dropbox Paper

The following description comes from the Google Play Store description of the app:

Grow bigger, brighter ideas with Dropbox Paper, a flexible workspace that brings people and ideas together. With Paper, you and your team can create, update, and collaborate on documents—and keep everything synced seamlessly across all your devices.

EDIT AND CREATE DOCS
Capture inspiration wherever it hits. Create new docs or make changes to existing ones—and keep projects moving forward from anywhere.

STAY UP TO DATE WITH YOUR TEAM
See everything that happens in your docs—like comments, shares, and @mentions—in one organized list.

POST AND REPLY TO COMMENTS
Add, view, and reply to comments right inside docs, so the conversations around work continue—even when you’re away from your desk.

PRIORITIZE KEY DOCS
Star docs and folders for quick access. Use folders to keep docs organized by project.

SHARE YOUR DOCS
Keep everyone on the same page by adding people from your team to your docs.

WORK OFFLINE
Get work done anytime, anywhere—even without an internet connection. With the mobile app, you can access, edit, and comment on your starred and recent docs, or create new docs while offline.