Updating the operating systems do not take much time. Apple users will actually see an alert on their devices, a red number, "1" that would be visible both on their Mac computers, including desktop and laptop device, and also on the iPhones and iPads.
The update specific for Mac is available for both macOS Catalina and macOS Mojave — the names Apple uses for the two most recent operating systems — and is designed to fix an issue that Apple describes on its site where "Processing maliciously crafted web content may lead to arbitrary code execution." This brings the macOS up to version 11.3.1. This is the same issue that Apple describes regarding the update for iOS 14.5.1. for iPhones and iPadOS 14.5.1 for iPads.
Apple routinely has security updates, including one in March 2021, and January 2021 as well. And It's always recommended that people plug their devices into a power source before making the updates, although these specific updates did not appear to take more than 5-10 minutes for each device.
The iPhone update is needed for Apple's phones including the iPhone 6s and later. All iPad Pro models should also make the update as well as iPad Air 2 and later, the iPad 5th generation and later, the iPad mini 4 and later and also the iPod touch (the 7th generation version.)
To check that your Mac is using the correct macOS, and has been updated, you can go to the Apple image on the upper left of a screen, and then,
- Click on the Apple
- Click on "About this Mac"
- Check that in the popup box it reads, "Version 11.3.1"
To check that your iPhone is using the correct iOS, and has been updated, go to:
- Settings on the iPhone and open this
- Click on "General"
- Click on "About"
- Look at "Software Version," and see that it reads "14.5.1."