Browser Extensions do exactly what the name suggests - they add other features or shortcuts to your browser. There are several brands of web browsers, and Google Chrome is the one most used worldwide.
Extensions are not really the same as plugins, and extensions haven't made it to tablets and smartphones yet.
From How to Geek
Where can you get browser extensions? For the Chrome browser, you can go to the Chrome Web Store. Other browsers have their own stores, such as Firefox Mozilla. Be aware, there have been instances of malicious extensions reported, though the main vendors do a pretty good job of watching them. Search for the extension you would like to use in your browser, then check out the reviews and when it was last updated. Frequent updates means it is being supported and maintained. Many of your favorite applications have browser extensions, such as a way to translate from one language to another. When I was taking Spanish classes, this was invaluable!
First, using the Google Chrome web browser, I navigated to the Chrome Web Store and searched for translate. I was looking for something highly rated and used by many. I chose Google Translate, and clicked on "Add to Chrome." I could then see the icon for that extension in the upper right corner of my browser window, above the favorites tool bar.
Now, when I am on the web and see a word or phrase I am not sure of, I can highlight it and using my mouse, right click. I am looking for that blue "G" icon and then I click on it.
Not only does it translate, but I can also listen to the pronunciation.
Browser extensions can add functionality and simplicity to web browsing. And they are easy to remove! Find the icon located at the top right corner of your browser window, right click and choose "Remove from Chrome."
To remove from Firefox, right click and choose "Remove Extension."
LastPass, the Password Manager I use, also has browser extensions for just about every web browser.