Apple has released the latest version of macOS High Sierra, 10.13.3, with bug fixes and stability improvements.
Here's how to download and install this and other updates for macOS High Sierra.
Select App Store from the drop-down menu.
Click Update next to macOS Sierra in the Updates section of the Mac App Store.
You don't have to manually update macOS every time a new one launches. You can turn on automatic updates and it will download in the background.