For desktops, saving a web page to your computer is the easiest way to download it. For chrome, select "More tools" > "Save page as." For Firefox, open the same menu and choose "Save page as." You can also right-click and select "Save as" or use the keyboard shortcut Ctrl + S on a PC. On Safari, go to File > Save as or File > Export as PDF. The keyboard shortcut for a Mac is Command + S.
On Android devices, open the three-dot menu icon, and tap "Download", which will download a version of the page for offline viewing. View all recent downloads by selecting the menu icon again and tapping Downloads.
In the iOS app, you can either tap the share pane, and select "Read Later" or open the browser's menu and choose "Read Later" to add the article to an offline reading list. From there, open the Chrome menu again and select "Reading List." Long-press a saved item until a menu pops up, then tap "View Offline Version in New Tab," and you're ready to read offline.
Like Chrome, in Firefox you can select the menu on the top right > "Save Pages As" to download web pages to your computer. The browser also give users an offline reading mode. Using the menu, select "More" > "Word Offline". This allows you to access your most recently viewed pages.
In the Android, open the browser's main menu, select "Page > Save as PDF" to download the file to your device. . When you're offline and need to access the PDF, open the main menu again, select "Tools > Download," and choose the one you want to read.
In iOS, open the three-dot menu, select "Add to Reading List." From there, navigate to the hamburger menu > Your Library > Reading list. Select the article you want to open, and it will be available to you offline automatically. For a desktop in Safari, go to "File" > "Save as" or "File" > "Export as PDF."
You can also save web pages to your Reading List by selecting Preferences > Advanced and checking the box next to "Save Articles for Offline Reading Automatically." For any Apple device, selecting the Share pane and clicking "Add to Reading List" will add any article you want to save.
Pocket allows you to save online articles for later, and sync them between your devices—Mac, PC, iOS and Android. It was acquired by Mozilla in 2017, so Pocket is now built into Firefox, but there are also extensions for Chrome, Safari, and Edge.