Unless you are extremely lucky, you will need a kext to enable your internet. Most ethernet built into motherboards can be used; however, a very small number of wifi cards are supported. If you have a prebuilt system or laptop, most likely you will have to purchase a new wifi adapter.
For a list of compatible hackintosh wifi cards see Hackintosh Wifi
Most likely you’ll be able to use your motherboard’s built in ethernet. First, find the type of ethernet card in your motherboard. This can be found in the manual or on the manufacturer’s website.