How do I get my Shopify products into Google Merchant Center?
Publish them to the Google and YouTube channel in Shopify, then fix whatever the feed rejects. The failure most stores have is simpler than a rejection: their highest value products were never submitted at all.
Check what is actually published
On one client account the quarter, half and whole beef products, the three highest value items in the catalog and 31.5 percent of attributed revenue, were published only to Online Store and Point of Sale. They had never appeared in a Google product listing.
Free listings are not ads
Free product listings cost nothing and are separate from paid Shopping campaigns. Keep them separate in reporting or you cannot tell which one earns.
What it moved
Orders from free listings went from 2.0 a month to 5.8. Measured against the channel's own recent baseline rather than its dead period, 16 percent more orders and 35 percent more revenue.
Real numbers from a live Shopify client account. Every result page carries the before, the after, and what the figure does not prove.