Hello Puneeth, Ben here - your Shopify Guru!
The sitemap is genereated automatically by Shopify. You cannot upload your own sitemap. If you need to modify what search engines index I would suggest you review our documentation around the robots.txt. You can use some liquid and meta tags to remove pages from being indexed. Our documentation can be found here:
I hope this helps! Feel free to reach out if you have any further questions :)
Ben C - Shopify Guru
I don't know if this is still relevant but I found a solution.
You'll have to upload your custom sitemap to your "files" tab in your store settings and copy the file's URL.
Then go to your navigation -> URL redirects and add a new redirect that redirects from your domain to the .xml file previously uploaded
will look something like this: mydomain.com/sitemap.xml redirects to https://cdn.shopify.com/s/files/*************/files/sitemap.xml?*****
Then submit your newly created URL to Google console, it seems that it has no problems with redirects
Hope I helped someone!
If you want more info, check out my reply on this post where I detail the SEO best practices and provide step-by-step instructions...