Fetch as Google was a tool in the old Search Console that let site owners see how Googlebot rendered and read a specific page, and request it be crawled and indexed faster than waiting for a normal crawl. It's since been retired and folded into the URL Inspection Tool in the current Search Console, which covers the same job, seeing how Google renders a URL and checking its indexing status, plus a good deal more diagnostic detail than the original tool offered.
The core use case hasn't changed even though the tool has: after publishing a new page or making a significant change to an existing one, running it through URL Inspection is the fastest way to surface a crawling or rendering problem, missing content, a blocked resource, an unexpected redirect, before waiting to find out the hard way that Google indexed something other than what was intended. It also remains the quickest legitimate way to nudge a freshly published or updated page toward faster indexing rather than waiting for Google's normal crawl schedule to find it.
