I had gone to create a Google Merchant account and in order to validate my website, I had to add my website URL. I tried several types of what will seem to be URL but they all failed to be verified.
My Shopify store name is Proverbia and hence http://proverbia.myshopshopify.com. However, the domain name, which I bought from Shopify and which is connected, and so http://proverbiamkt.com. See the attached printscreen. (I could not attach the printscreen, but a copy of the message is attached).
I had several ways to verify the website but each gave me a 404 Page Not Found even though I could see my website and store with the instruction "Continue Shopping", which worked.
What is the proper URL for my website and store?
Verification failed - We couldn't locate your verification file.
Claiming failed - You must verify your URL before you can claim it.
Verify and claim your website URL using one of these methods"
1) You can claim your website by adding the HTML tag, ie the meta tag. URL HTML File is no longer possible as you can't upload html files to Shopify.
2) You can also first claim your website via Google Search Console, however the process is the same.
Make sure you choose alternative method, and select html tag. Then add the tag to your theme.liquid file
Hope this helps.