John Mueller says: “Google doesn’t care whether URLs end in .html, .php, .asp, or have no parameters at all. No matter what a URL ends with it will still show up in search the same way in search results.”
Removing Extentions from URLs are the equivalent of restructuring a site, and old URLs will need to be redirected to the new ones. Restructuring a website will take time for it to be reprocessed by Google.
If you’re in a situation where you absolutely have to remove extensions from URLs, like moving to a content management system that doesn’t allow them, John Mueller recommends doing this during a when you are less dependent from Organic/Search traffic.
There is also a tool not for extensions but for Parameters.
You can use the URL Parameters tool to indicate the purpose of the parameters you use on your site to Google.
The preferences that you set will encourage Google to crawl the preferred version of your URL (Canonical Version) or simply prevent Google from crawling duplicate content on your site. This also contributes slightly to Crawl Budget