Make sure that your website is compliant with Google's policies
Google Shopping Policies: https://support.google.com/merchants/answer/188484
User Safety Policy: https://support.google.com/merchants/answer/2768342
Billing Policy: https://support.google.com/merchants/answer/2704226?hl=en
Sites must contain the following pages:
Payment Options / Payment policy
Terms and Conditions
The links in the footer of your site should be very visible.