How to Update MacOS and Other Applications How to update Mac-OS, Safari, Messages, Mail, Music, Photos, FaceTime, and Calendar.   Click the apple menu icon on the top left corner of the screen.   Click on system preferences.   In the new window, click on Software Update.   If an update is available, click on upgrade now.   Click Agree.    Allow the program to download. Make sure any important documents are saved and closed during this process.   Once the download is complete, the computer will restart to complete the download.   After some loading, you will need to login back onto your computer. Your OS will be updated, along with the stated applications.