Http response status code 301 (i.e. “Moved Permanently”) is a combined way of implementing a URL forwarding. The response status code tells users and search engines that the page has moved permanently and that all links pointing to this URL should instead now point to the new URL.
Use a 301 Redirect if you are moving a page to a new URL permanently.
Change the search result without losing ranking
A 301 Redirect is a simultaneous instruction to Google and other search engines to exchange the old search engine result with the result that is now being directed to. As long as the new page is identical, it will normally retain its full ranking.
A 301 Redirect is server-side and the notification that the page has moved to a new URL is transmitted before the page is loaded.
Search engines are quick to follow a 301
If a 301 Redirect is correctly implemented, Google and other search engines will be quick to follow the redirect and update the address in their index to the new correct URL.
301 Redirects retain the value of the link
You retain the value of the link from incoming links that point to the old URL when you set up a 301 Redirect. Therefore 301 Redirects are also “Best Practice” when a URL is due to expire or be permanently replaced.