Extension setting services allow you to add extensions directly to resources in your account, without having to go through the trouble of manually setting up feeds.
You can set up extensions at the customer, campaign, or ad group level by using one of the following services:
The actual workflow of using these three services is identical. You must use the one that corresponds to the type of resource you would like to attach your extension to. A customer extension setting will apply to all ads in an account, a campaign extension setting will apply to all ads within a given campaign, and an ad group extension setting will apply to all ads in a given ad group.
The examples in this guide will use the CampaignExtensionSettingService, but
they should be easily adaptable to use with either of the other services.