Manjaro comes with a graphical update manager. This application will notify us when there are any available updates from the repository. We can then update Manjaro directly from this application.
But some of Manjaro users like me prefer the command line way to perform update. But if I can say, this is not a "better" or "worse" way to update Manjaro via Terminal. Its only a preferable way. You may use the graphical way, same as the command line way.
In case you need to update Manjaro via command line, you may follow these steps.
Open Terminal session and use this command to sync repository database
sudo pacman -Syy
Once completed, you can continue with this command to perform upgrade if any upgradeable packages.
sudo pacman -Syu