Different Drivers

We have different driver classes available in Web Driver. Each browser has a different driver implementation in Web Driver. For few browser separate external entity is not required for few other separate external entity is required. For that user should download driver server for each browser. For Mozilla Firefox and HTML separate external driver server is not required, other browsers like IE, Chrome Opera, Safari and Microsoft Edge separate external driver server is required.
Note: If you are using Mozilla Firefox version 47 and above you should download external driver server like other browser.

From where user will download the driver servers
Below is the download like

http://www.seleniumhq.org/download/