Hi Victor,
Segmentation depends on the fields available in the report; therefore, each report can be segmented differently. To segment a report via the API, all you need to do is to add the segmentation field to the report. For example, to segment the Campaign Performance Report based on the type of the network (search, display, youtube etc), just add the field AdNetworkType1 to the report. Similarly, you can use other fields for segmentation, such as device type (desktop, mobile, tablet etc), type of the network (search, display, youtube etc), date and more.
You can the following reports for your purpose:Locations - Geo Performance ReportInterests & Remarketing lists - Audience Performance ReportDemographic - Age Range Performance Report
A consolidated list of all reports and their respective segmentation fields is available here. For more information on segmentation please refer to this article.
Regards,
Vishal, AdWords API Team