Windows Update automatically installs important updates as they become available. When the Windows 10 Update is ready for your device, it will be available to download from the Windows Update page in Settings. Choose a time that works best for you to download the update. You may then need to restart your device and complete the installation.
...
Select Start > Settings > Update & Security > Windows Update , and then select Check for updates. If updates are available, install them.
Note
If any windows updates isn't offered automatically through Check for updates, you can get it manually through the Update Assistant.
If you run into problems updating your device, including problems with previous major updates, see common fixes at Troubleshoot problems updating Windows 10, or use Fix Windows update issues to step you through the troubleshooting process.
If you're warned by Windows Update that you don't have enough space on your device to install the update, see Free up space.
If you experience internet connection issues while updating your device, see Fix network connection issues in Windows.
If you're still running Windows 7 or Windows 8.1 and want to make the move to Windows 10, you can learn more at Upgrade to Windows 10: FAQ.
Get more info about Windows Update.
Check for updates