Do not expect a miraculous uptick in visual quality -- those ray tracing effects only apply to shadows, and that means you're going to TBC Classic Gold see a softer, more realistic areas of darkness when you're making use of the choice. This will not revamp the game's whole lighting model, and that means you won't get as transformative a result as in, say, Minecraft's RTX implementation.
You'll need a GPU that supports ray tracing tier 1.1, using the newest drivers, as well as the May 2020 update for Windows 10 -- also, clearly, you'll need to be using DirectX 12.
You can head into the Blizzard site to opt-in for an opportunity at beta access, too.
The folks at Wowhead have captured a load of buy WOW Burning Crusade Classic Gold comparison shots to show what those ray-traced shadows look like. It's a pity WoW ray tracing won't go past shadows for today, since the stylised design and easy character models would appear incredible beneath the spotlight of exceptionally realistic lighting.