A 301 Redirect is a command sent by web servers to redirect a given URL towards another URL. These redirects are often set up to present web users with an appropriate webpage when the URL has been changed during editing.
A 301 Redirect is set up to ensure that both internal and external links from a URL are followed to the correct URL, or to ensure traffic to an old URL is rerouted to the new URL. Because it’s a command understood by Google’s bots, the 301 Redirect passes the page rank of the previous URL to the new URL.