How are Shopping ads created?

The campaign and bid settings in Merchant Center helps Google’s system determine which ad will show for a user’s search query.
Keywords in Google Ads help Google’s system determine which ad will show for a user’s search query.
The product information in Merchant Center and the bid set in Google Ads helps Google’s system determine which ad will show for a user’s search query.
Keywords in Google Ads and the bid set in Merchant Center helps Google’s system determine which ad will show for a user’s search query.