how to connect Wi-Fi from dell tower to wireless router

I have a Bravia TV and planning to buy a Dell Inspiron 3000 Series 4th Gen. Intel Core i5 3.4GHz 1TB Desktop tower. The tower says it has Wi-Fi connectivity. I am planning to connect the tower to my wireless router. Is that possible or do I need to buy a usb wifi adapter to connect it? Is the tower sufficient for a Wi-Fi connection? thanks in advance for the replies!