Programmatic architecture allows advertisers to deliver a personalized ad with the help of DMPs, or, Data Management Platforms, that store a user's information such as age, demographics, and location.
External References
https://www.iab.com/ - IAB(The Interactive Advertising Bureau) is one of the popular websites can get good information. Some people ignore / make a fool if you have no information about iab and its events.
Technical Elements for Programmatic Advertising