This guide assumes you already have your WordPress.com site set up and your site is verified with Google Analytics / Google Search Console.
By default WordPress.com prepares a sitemap for you.
To see it simply copy and paste the mock url below (Option 1) into your browser search bar and edit it to reference your site. If you own a custom domain omit the reference to WordPress as demonstrated in (Option 2).
Once you have verified the sitemap url is correct add this sitemap to Google Search Console.
Do this by logging into Google Search Console and clicking on Sitemaps on the left hand side of the main window.
In the sitemaps window there will be the option to paste the copied url under “Add a new sitemap” and Submit it.
Once the url is submitted your sitemap will be saved under “Submitted sitemaps”.