From the site :

http://www.esa.int/Our_Activities/Human_Spaceflight/International_Space_Station/Where_is_the_International_Space_Station

The European Space Agency (ESA) is one of the international space agencies involved in the management and participation in the International Space Station (ISS). 

Participation in the ISS

 ESA is one of the main partners in international cooperation for the ISS. European laboratories, such as the Columbus Laboratory, are essential elements of the station and are used to conduct a wide range of scientific experiments.

Scientific Research

 ESA's European astronauts aboard the ISS actively participate in scientific research. European experiments cover various disciplines, including biology, physics, medicine, and Earth sciences. The goal is to better understand the effects of microgravity and develop new technologies.

European Modules

 ESA has contributed specialized modules to the ISS. The Columbus Laboratory is the primary European research laboratory on the station, while the Automated Transfer Vehicle (ATV) was used for cargo transport and resupply.

Astronaut Training

 ESA trains European astronauts for missions to the ISS. These astronauts participate in long-term missions, performing scientific and maintenance tasks.

Technical Support

 ESA provides technical support for scientific and operational activities on the ISS. This includes mission control, experiment planning, and supply management.

International Collaboration

 ESA collaborates closely with other space agencies involved in the ISS, such as NASA and Roscosmos, to ensure the success of missions and the continuity of scientific research in space.