The two major editions of Windows 8, Windows 8 (standard) and Windows 8 Pro, can each come in either 64-bit or 32-bit format. Knowing which type of Windows 8 you have is important so you choose the correct drivers and software for your operating system.
For example, if you have the 64-bit version of Windows 8 Pro installed and need to update the drivers for a piece of hardware, like your video card, you must download and install the drivers labeled "64-bit" by the manufacturer. You can not install 32-bit drivers on a 64-bit version of Windows 8, nor vice versa.
Fortunately, it's extremely easy to determine if the copy of Windows 8 you have installed is 32-bit or 64-bit.