Sync keeps every device on the same page, and it is part of the Pro subscription.
Getting it running
Sign in with the same account on each device and sync takes care of itself. The first sync uploads your existing library, which can take a while on a big one, and after that changes move as you make them.
When it runs
Automatically: when the app starts, when you return to it, every fifteen minutes, and a couple of seconds after you stop editing. The Cloud Sync tab in Settings shows when the last sync happened and has a Sync Now button for the moments you want to force it.
What travels
Notes, folders, tags, drawings, flashcards, quizzes, mind maps, attachments, chats, the search index and your settings. Settings syncing is why your prompt templates, personalization and even panel layout follow you between machines.
Your local copy stays
Sync does not move your notes off your machine. The local database is still there and still works with no connection, and sync keeps the copies in step. If you stop subscribing, the notes on each device stay on that device.
If something looks off
Sync retries failed runs on its own. A note edited on two devices at once resolves to the most recent change, and version history keeps the earlier text reachable.