Sitemaps are automatically generated by Shopify for all stores. You don't have to manually create one. You can, however, add the sitemap to your Google Search Console account to help with SEO.
Here is a step-by-step guide:
Locate your Shopify sitemap: Your Shopify store's sitemap URL generally follows this format:
yourstorename with your actual store’s domain name. You can copy this link for use in the next steps.
Set up Google Search Console: If you haven’t already, set up your shop on Google Search Console. You'll need a Google account to do this. Once your account is set up, click on 'Add Property', and then enter the URL of your website.
Verify your website: Google needs to confirm that you're the owner of the website. You can do this by adding a meta tag to your website, uploading a HTML file to your server, via your domain provider, or through Google Analytics. If your site is on Shopify, the easiest method is usually through the domain provider.
Submit your sitemap: Once your site is verified, go to 'Sitemaps' on the left side menu. Paste the sitemap URL you copied earlier into the 'Add a new sitemap' field and hit 'Submit'. Your sitemap will be submitted to Google for indexing.
Please remember that it may take some time for Google to crawl and index your site.
Note: While Shopify automatically generates a sitemap, you cannot customize this sitemap due to Shopify's restrictions. Any changes you want to make to URLs indexed in the sitemap must be done at the page level in your Shopify settings.