Download Bluestacks here. (Available for both Windows and Mac)
To root Bluestacks v2.6.104 (the latest version available as of the date I write this, March 18, 2017) you can use BSTweaker. It can be downloaded here. (To download, click once on “BSTweaker2” so that it is higlighted (turns blue), then click the 3 dots at the upper right of the screen and choose “download.”) Once you have it downloaded, unzip and run it (Bluestacks must be running when you do this.) A window will appear. Click the “Helpers” tab and then next to where it says “Root for BlueStacks" click the “Patch” button. A green success message will show up at the bottom of the window to indicate that the patch was installed correctly. Here is a YouTube video that shows how to root Bluestacks using BSTweaker.
Unfortunately there is no way that I have found to install Xposed on Bluestacks - if you Google it there are quite a few tutorials out there but I have never gotten them to work. You will need to download and use rootpatched APK’s in order to bypass the SIF root check. More info on that can be found here.
