Question: How do you know which product pages have been indexed by Google? If they haven’t been indexed, how is SEO effective?
Answer:
Go to google search and type in the following–
site:mywebsite.com
For example= site:linkedin.com
You’ll see something like this: https://www.google.com/search?q=site%3Alinkedin.com
Doing this will show you all the pages that Google have already indexed of this site. This will include your product pages from Shopify. This is something that’s useful if you have a few pages.
If you have a lot of pages, you should use a tool such as Google Search Console (free): https://search.google.com/search-console
After you set it up (wait a day for data to be processed), go to: Coverage > Submitted and indexed (click on “Valid”, to show you what’s indexed)

At the bottom, you’ll see them listed. Click on the appropriate row and a list will pop up for you. You can export this list as well, if needed.
Depending on your goal, a SEO tool, such as Ahrefs or MOZ, may be more beneficial. In those tools, you can see which pages are indexed AND which keywords they are ranking for. This is a better way to track how effective your SEO is going.