To date Joomla article SEF (Search Engine Friendly) URLS contain the article ID. However with the release of version 3.8, Joomla includes a brand new router which allows you to remove this ID/number from your SEF URLs . From an SEO perspective this is a lot more favoured as it gives you a cleaner, more self explanatory URL.
Considering the effect the new router has on your site URLs, this feature it is not enabled by default.
Enabling the new URL router
From your Joomla administration navigate to your Article Manager (Content -> Articles).
In the page toolbar click the Options button to open your article options.
Select the Integration tab
Firstly set the URL Routing option to Experimental
Below you can now set the Remove IDs from URLs option to Yes
Important: Please note that by enabling this feature you are changing your site URLs. On a new site this is insignificant however on an existing site this will have serious implications to inbound links to your site, essentially rendering them broken. If you have a relatively small number of URLs on your site, a work around is to create redirects from your old URLs to your new URLs.
Creating URL redirects from old to new URLs
Navigate to Joomla’s Redirect component (Components -> Redirect)
At this point you may be asked to enable your Redirect Plugin. If so following the link provided to do so. Once enabled return to your Redirect component
Click the New option in your component toolbar
In the Expired URL field add the old URL you wish to redirect from. In reference to this article this would be the URL with the article ID
In the New URL field set your new URL for your article.