A Magento 2 shop can be crawled by search engines like Google Search more efficiently when they receive a special file where links to all pages on a website are gathered. This file is called a sitemap and it helps search engines to build a relationships between pages, files and other content on a site, which in turn helps its promotion in search engine rankings.
Embedded Magento functionality doesn't allow you to add URLs from this magento plugin blog to the default Magento's sitemap. You can add URLs of your blog pages to the sitemap by using another Mirasvit extension Advanced SEO Suite. It can help to greatly improve your store's search engine ranking, and one of its functions is as an advanced sitemap generation. Such an advanced sitemap will include URLs from the blog plugin magento. For more information, check the page of this extension and its user manual.