Diana here from the Shopify Support Team.
Your sitemap is built using your store's primary domain. So, if your store's primary domain is busylittlebird.com, then your sitemap would be found at busylittlebird.com/sitemap.xml.
If you haven't already, you should take a look through our instructions on how to find and submit your sitemap. It should make things a lot clearer!
Hope this helps! :)
If you want a sitemap page that is beautiful for your customers to read and helps them quickly locate the information, you would want to try this app: https://apps.shopify.com/sitemap-page.
It's more affordable than other sitemap apps on Shopify and have more functionalities such as customizable page title, description, and layout. It also support pagination feature which is best fit for shops that have thousands of products.
If you're looking for a Shopify app that will automatically generate a beautiful HTML sitemap for your store in seconds, you'll want to install Sitemap Builder. https://apps.shopify.com/sitemap-builder?ref=adolab
Sitemap Builder lists every product, collection, page, blog, and article on your entire site on one convenient page. It also helps to improve your SEO (search engine optimization) because it can be easily crawled and indexed by Google. This increases your overall ranking on search engines & helps you show up more often in search results. Not to mention, an HTML sitemap helps your customers easily find what they are looking for.
Sitemap Builder is better than other sitemap apps becuase it offers a free 1x design, 24/7 customer support, fully customizable layout & text, and there's no cap on the amount of products you want to list on there. It also has a 5 star rating, & is trusted by Shopify sellers who use it everyday to list hundreds of thousands of products.