I currently have Sims 4 download on my Macbook. I would also like to download and play on my desktop windows machine. Is it possible to play the same account on both so I don't lose my current world/progress?
@fyremt I've moved your post to the Sims 4 PC tech section.
You can download the game itself on as many computers as you like, for free. (You can only play on one computer at a time, of course.) But your saves need to be manually transferred back and forth if you want to play the same sims on both machines.
All your user-created content is located inside Documents\Electronic Arts\The Sims 4, and most of the files in that folder will work equally well in Windows and macOS. To transfer progress from one computer to another, you'd simply need to copy the contents of the Saves and Tray folders inside the Sims 4 folder to the new computer. You could do this with a USB stick (make sure it's formatted to work on both operating systems) or via cloud storage. There's an iCloud app for Windows, or you could use a free filesharing service like Google Drive, Mediafire, etc.
Be sure to install the same mods and cc, if you use any, on both systems as well. While these files should also transfer between Windows and macOS, it doesn't always work, and it might be easier to just download fresh copies.