XML sitemaps can help boost your site's visibility and ranking in Google's search results. Here are some tips to help you get started:

1. Create a sitemap that includes URLs from all the sites that you want to cover.
2. Include the sitemaps in a sitemap index file if you prefer and work with that sitemap.
3. Submit your sitemap to Google using Google Search Console³.

An optimized XML sitemap is one of those signals that can lead to faster indexing and higher rankings¹.

Source: 
(1) How to Create an XML Sitemap (and Submit It to Google) - Ahrefs. https://ahrefs.com/blog/how-to-create-a-sitemap/
(2) How to Use XML Sitemaps to Boost SEO - Search Engine Journal. https://www.searchenginejournal.com/technical-seo/xml-sitemaps/
(3) Build and submit a sitemap - Google Developers. https://developers.google.com/search/docs/crawling-indexing/sitemaps/build-sitemap