Hi Ramanajee,
Thank you for reaching out. Please see
here for more information on setting up Dynamic display ad feeds. As explained, you can use the API to create Feed, FeedMapping, and FeedItem objects for use with your dynamic remarketing ads. You can follow
this example and
this example. Additionally, there is more information available
here. You will need to use the
CustomPlaceholderField enum for a custom type as shown in your screenshot.
Regards,
Mitchell
Google Ads API Team

ref:_00D1U1174p._5001UXWD6P:ref