When a new update is available, your Apple Watch notifies you. Tap Update Tonight in the notification, then go to your iPhone to confirm that you want to update overnight. At the end of the day, leave your Apple Watch and iPhone charging overnight so the update can complete.
To Update Your Apple Watch Using Your iPhone
To Update Directly on Your Apple Watch
— Make sure that your watch is connected to Wi-Fi.
If your Apple Watch has watchOS 6 or later, you can install subsequent updates without your iPhone:
— On your watch, open the Settings app.
— Tap General Software Update.
— Tap Install if a software update is available, then follow the onscreen instructions.
To Update Apple TV 4K or Apple TV HD — Go to Settings System Software Updates and select Update Software.
— If there’s an update, select Download and Install. — Wait for your Apple TV to download the update. Don’t disconnect or unplug your Apple TV until the update completes.