If you want to verify your marketplace using Google Search Console, you can do it by adding the content of Google's verification tag in Console.
Add your website to Google Search Console
Log in to Google Search Console account with your Google account at https://search.google.com/search-console/about
Add a new Property of type "URL prefix"
Follow the instructions to configure your website
When asked to verify the ownership, choose chose "HTML tag" as the verification method
From the "google-site-verification" meta tag that is displayed, copy only the part in "content", not the whole tag. Or if you copy the entire thing, remove everything except the content "key".
<meta name="google-site-verification" content="H4Nfk56gtFHffz3fM4ekqe9aNTtGwDvTloHHE4FWx2s" />
If the tag is the one above, you would only copy:H4Nfk56gtFHffz3fM4ekqe9aNTtGwDvTloHHE4FWx2s
Add the content of the Google Search Console verification tag to your marketplace in Console
Log in to Console.
Paste the content of the Google Search Console HTML verification tag you copied earlier into the "Google Site Verification tag content" field.
Save changes.
Go back to Google Search Console to confirm the ownership verification.
Voilà! Your marketplace is now verified in Google Search Console!
Add your sitemap to Google Search Console
In your search console property
Go to the Sitemaps menu on the left.
Click on "Enter sitemap URL" field under "Add a new sitemap.".
Add the sitemap index file by entering
sitemap-index.xmland click SUBMIT.You should see the status "Success" appear in green.
At first, it may should "Couldn't fetch". Wait a few minutes, and refresh the page. Google takes a minute to crawl and process your sitemap file.
That's it! Google now knows about your sitemap file and will index its content over time.
Note: You don't need to add the other three sitemap files. It takes a few minutes for Google to recognize the content, but adding the index file is enough.
You can learn more about the marketplace sitemap files in this article. If you receive an error when configuring your sitemap, make sure that your information is correct
More information about Google Search Console
You can learn more about Google Search Console from Google support.