Step One: If you haven’t got one already, follow the steps to create a free Google Search Console account here: https://search.google.com/search-console/about
Step Two: Once set up, go to the URL Inspection Tool (in the left hand navigation area) and enter your full website domain name (including https://) in the search box.
Step Three: Google will check the URL (which should confirm there are no results) & you can click the ‘Request Indexing’ button.
Using the URL Inspection Tool to request indexing can take a couple of weeks, so if you know the location of your ‘sitemap’ it may be quicker to submit that instead, using the Sitemap Section which is also available via the left hand navigation area.
The image below shows you the 3 step areas, but as you would expect in my case, my website has been indexed, so I have no need to request indexing again at this time.
You can also use this internal Google Search inspection process to check a single URL. For example if you have released a new page or blog post, pop the full individual URL in here and again Google will let you know if they have indexed it.