If a buy a sims 4 disk version that says digital download for Mac, would I be able to download it on a Windows 10 computer without a disk drive?
Yes, as long as you have an Internet connection.
Download and install Origin.
Log in to Origin and if the Code has not already been redeemed do so and the download starts.
If it has been redeemed log in to the account you have it on and click it in your game library.