Use Software Update

Choose System Preferences from the Apple menu , then click Software Update to check for updates.
If any updates are available, click the Update Now button to install them. Or click “More info” to see details about each update and select specific updates to install. You might be asked to enter your administrator password.
When Software Update says that your Mac is up to date, the installed version of macOS and all of its apps are also up to date. That includes Safari, Music, Photos, Books, Messages, Mail, Calendar, and FaceTime.
To automatically install future updates, including for apps that you got from the App Store, select “Automatically keep my Mac up to date.” Your Mac will notify you when updates require it to restart, so you can always choose to install those later.

Update the software on your iPhone, iPad, or iPod touch

Open the Mac App Store and check for updates until it reports that no Safari or security updates are available.

Learn how to update your iPhone, iPad, or iPod touch to the latest version of iOS or iPadOS.

Sep 12, 2013 Apple on Thursday released the latest 10.8.5 maintenance update for its current Mountain Lion operating system, bringing a host of bug fixes and performance improvements including a fix for Mail.
Aug 12, 2009 This update upgrades Safari to version 4.0.2. See this article on how to validate the authenticity of this update. For explanation of what a SHA1 digest is, please visit this website: Mac OS X: How to verify a SHA-1 digest. For detailed information on Security Updates, please visit this website: Apple security updates.

Learn how to get updates for earlier versions of macOS that don't include Software Update preferences.
You can also use the App Store to update apps or redownload apps that came from the App Store.
Learn which macOS your Mac is using and how to upgrade to the latest macOS.
When your Mac is connected to a Personal Hotspot, large updates don't download automatically.