If it's just an update to the current version of the Mac OS you need to install jump to this section: Install an update to Mac OS If you want to know how to update your apps on your Mac, read this: How to update all your Mac apps.
When the upgrade install is complete and Mavericks is up and running, all of your important data will be right where you left it, ready for you to use.
Updating your Mac to the latest version of the Mac operating system is really easy, and not nearly as time consuming as it used to be.
An initial, early version of the system, Mac OS X Server 1.0, was released in 1999.
The first desktop version, Mac OS X 10.0, followed in March 2001.
Apple changed the original name "Mac OS X" to "OS X" in 2012 and then to "mac OS" in 2016, adopting the nomenclature that it uses for their other operating systems, i OS, watch OS, and tv OS.
The latest version of mac OS is mac OS 10.12 Sierra, which was publicly released in September 2016.If you choose Skip This Version, but later decide to check for an update, you can launch the Java Control Panel by clicking the Java icon in System Preferences. If you choose Remind Me Later, you will be reminded of the update the next time you run Java.Upgrading from a previous version of OS X is the most common method of installing OS X Mavericks.However, there are a few things we recommend you do first to ensure things go smoothly, we run through these, as well as instructions for downloading and installing the latest version of the Mac OS in this tutorial.We'll also guide you past the potential headaches and any problems you may encounter.Sierra will probably run significantly slower than Snow Leopard and I'd recommend at least 4GB and an SSD or at least 8GB of RAM.