When a user conducts a search on one of the search engines such as Google, your shopping ad would be displayed if the user’s search contains relevant keywords for your products.
In order for the shopping campaigns to know about your products, you will need a shopping feed to plug into these advertising platforms. A shopping feed will contain a list of all of your products with several important details about each product. It will include details such as product name, product description, product image and price. From there, the shopping campaigns will be able to read your shopping feed to know what keywords will be relevant to your products.
Google Merchant Center have options to host your shopping feed. The merchant feed transcribes your shopping feed into the format that the advertising platform needs it to be in for the shopping ads. Within the merchant center you will be able to add additional details such as the shipping and the tax information used on your website. You will also be able to check for any errors that may be in your shopping feed within your merchant center.
Due to the nature of a shopping ad unit, these ads usually see a higher click-through rate than traditional search ads. Having an image of the product paired with the text helps attract users to your products. With having a higher click-through rate, that also tends to lead to a lower cost per click than your typical PPC search ads maybe able provide. When the user clicks on your product ads, it takes them to the exact product page on your website. This makes it very easy for the user to be able to navigate to the information that they are seeking.
For this reason, shopping ads see a higher conversion rates than most search campaigns. Being able to deep link to each product page is very powerful and makes the process seamless for the user. The easier you can make it on the user with your advertising, the better your ads will perform.