Redirection
As websites progress over-time it is common for page URLs to change here and there. This may be intentional to improve the SEO score or perhaps a page on the site needs to be deleted for no longer having accurate information for the company. Whatever the case may be we want to make sure that we try and preserve as much of the SEO score for the old URLs as possible by redirecting those old URLs to new valid URLs. For example, a client sells Christmas tree permits on their website. The page that talks about these permits URL is set as santatrees.com/permit-0943232/ but we want to improve this page so we change the URL to something like: santatrees.com/utah-valley-christmas-tree-permits/.
So once a page URL has changed, we need to make sure that the old page gets redirected. On WordPress websites, we most commonly use a plugin called Redirection which lets us add redirects one by one or we can create a spreadsheet of redirects and upload them all at once.