The European Commission (EC) is the 'engine room' of the EU. It is one of 3 main EU institutions; the other two are the European Parliament (EP) and the Council (of the European Union).
The Commission prepares legislation for adoption by the Council (representing the member countries) and the Parliament (representing the citizens).
It administers the budget and the policy programmes (Agriculture, Fisheries, Research etc.) in cooperation with authorities in the member countries. The EC also services the 28 EU Commissioners.
Visit http://www.europa.eu if you want to learn more about the EU, or call the free service number 00 800 6789 10 11 from anywhere in the EU, they speak all 24 official languages.
To contact the European Commission: https://ec.europa.eu/info/contact_en