Are you talking about Favorites in Internet Explorer or what used to be called Favorites in Windows Explorer (which is File Explorer in Win8 and later)?
What had been Favorites in File Explorer still exists, but the terminology has changed to "Quick Access" instead of favorites. This webpage on
How To Add Folders To Favorites in Windows 10 may or may not be helpful, depending on how accessible it is. It was written in 2014, and at that point in the Windows 10 Previews the term "Favorites" was still being used. The step-by-step sequence he gives after an opening introduction that begins, "Favoriting a folder in Windows 10 is extremely easy," is still technically correct with the exception of what had been the Favorites button is now the "Pin to Quick Access" button. Quick access folders and files are also presented automatically at the top of the tree view in File Explorer, and files you frequently use will end up showing up at the end of the Quick Access area but will migrate in and out depending on if you continue to use a given file frequently or start accessing something else more frequently that supplants it. Pinned things remain in Quick Access, just like they did in Favorites. By the way, if his step by step instructions are accessible, you do not have to expand the ribbon, you can simply hit ALT+H to get focus on the Home ribbon, followed by PI to pin the folder you've got selected to Quick Access. If the webpage is not accessible I'll be happy to copy/paste a plain text version.