Windows Defender can be updated manually or automatically.
Manual Update:
1. Open the Windows Defender application. You will see the Windows Defender home screen.
2. On the left panel, click on Update & Security.
3. Select Check for Updates and it will start scanning your system for any available updates.
4. If any updates are found, it will show the list of available updates. You can select download and install them or let Windows Defender do it automatically.
5. Once the update is completed, restart your computer.
Automatic Update:
1. Open the Windows Defender application and go to Update & Security.
2. Click on Automatic Update Settings and make sure that the Automatic Update option is enabled.
3. Enter the time when you would like Windows Defender to check for updates in the Schedule a Scan box.
4. Click on Apply and close the Windows Defender window.
5. Windows Defender will now check for updates automatically at the specified time.
6. If any updates are found, it will download and install them automatically.
7. Once the update is completed, restart your computer.