Re: I bought a disc version of sims 3, how do I update the installer?

@DumplingDrawer  Your disc copy should have a product code printed on the back of the insert inside the case.  Register this in Origin and download Sims 3 from your game library.  This should work in both Windows and macOS, although on a Mac, you'll need to make sure you're downloading the version that says 64-bit on the game tile.  The older 32-bit version doesn't run and won't even install in macOS Catalina or newer.  The Windows version is 32-bit only.