Since the anniversary update to Windows 10 the Edge browser has been able to get extensions. Unfortunately, you have to get them from the Windows 10 store. Though it is easy to find all of them.
First, click the three dots on the upper right-hand side of the browser.
Then look towards the bottom to find Extensions and click it.
Then click “Get extensions from the Store”
BAM AND THERE IT IS.
Not a whole lot to choose from. I personally have Reddit Enhancement Suite, Last Pass, and Adblock Plus installed. As time goes on there should be a lot more to choose from. Now that there are extensions if more people will start to use Edge more.