About Thunderbolt 3 & USB-C
Thunderbolt 3 uses a USB-C connector, however, not all Windows PCs that have USB-C ports also support Thunderbolt 3. The USB-C connector is also used for other protocols such as USB 3.1 and USB 2.0, so you'll need to make sure that your computer's USB-C port supports Thunderbolt 3 before attempting to connect a UAD Thunderbolt device (via a qualified Thunderbolt 3 to Thunderbolt adapter).
Check the documentation for your PC
One way to tell if your Windows PC supports Thunderbolt 3 is to check the manual and other documentation. If the computer supports Thunderbolt 3 this will typically be a main feature listed in the manual and on the product page for the computer on the manufacturer's website.
Check your USB-C port
Some USB-C ports, such as the ones pictured below, have a Thunderbolt logo printed next to them to identify the ports as Thunderbolt 3 compatible.
USB-C ports with the Thunderbolt logo
Check the Thunderbolt 3 compatibility list
Thunderbolt 3 certified products are listed here.* Make sure to select "Windows" from the Operating System menu and "Thunderbolt 3" from the version menu to filter the list for compatible results. If you're looking for a specific computer model you can further filter the results using the "Category" and "Company" menus.
*All system requirements still apply. Intel lists some motherboards at this link that do not have Thunderbolt 3 built-in via USB-C, but rather come with a Thunderbolt 3 PCIe add-on card included from the manufacturer. Thunderbolt 3 PCIe add-on cards are not fully tested or qualified for use with UAD Thunderbolt devices.