The Sims 4 downloads to your Origin library, which is the platform used to purchase and play the game.
After purchasing the game from Origin, it will automatically download to your library. You can find the downloaded game files in your Origin library, which is located in the "My Games" tab.
You can also manually manage your downloads by clicking on the "Downloads" tab in Origin. Here, you can pause, resume, or cancel downloads.
The specific location of the downloaded game files will vary depending on your operating system and computer settings. However, it will usually be found in the "Documents" folder, under "Electronic Arts", and then "The Sims 4".
If you have any trouble locating your Sims 4 download, you can always contact EA Support for assistance.