If you buy a Cubase 12 or 13 license today, you technically cannot download Cubase 10. However, Steinberg sometimes offers previous versions in your "My Products" page. Check your account; if you bought Cubase years ago, version 10 is permanently in your library.
: Get the latest version of the Steinberg Download Assistant from the official Steinberg website. Sign In : Log in with your Steinberg ID. cubase 10 download
If you already have Cubase 10 installed, download the Update 10.0.60 to access the final maintenance fixes for the version. If you buy a Cubase 12 or 13