When you insert the disc, the console will automatically download the latest Title Update (patch) and any free compatibility updates. You do not download the full game — it installs from the disc, but patches download online.
If you bought Forza Horizon digitally on the Xbox 360 at any point before the store closure, you can redownload it for free. horizon download xbox 360
Instantly unlock trophies and challenges for games that are too difficult to beat normally. When you insert the disc, the console will
: Transfer game progress between different profiles or extract and inject save files using a USB drive. When you insert the disc