One of the best things about using Netflix to watch content offline is the quick transfer speeds. Netflix makes it easy to search for stuff to watch by genre or keywords. Sadly, there's no Netflix app for Mac or Linux, so you can't watch Netflix offline on those platforms. There's a Netflix app for Windows 10 in the Microsoft Store, and you can use the Android app on most Chromebooks.
If you want to know how to download movies on a laptop with Netflix, it's simple: you need to use the desktop app instead of the browser. Not all content is available to download, but just look for the Download button on the movie's description page within the iOS or Android app. You can watch movies offline on Netflix with your regular subscription, and downloading content doesn't count towards the number of screens you're allowed to view on.