What do you have to do to be in the European union?

A citizen of the European Union is someone who is a full citizen of a EU member state. If you are a full citizen of an EU member state then you are automatically a citizen of the European Union.

This supernational citizenship effectively makes all citizens of the European Union equals. It entitles citizens of one EU country the same rights as a native citizen of any another EU country. Europeans are free to travel, live and work in any EU country, and they will be treated as if it where their home country. It also permits them to vote and stand for election in local elections in their host member state.

It also has relevance internationally, an EU citizen can for example make use of an embassy of any EU country while outside the European Union.

European Union citizens are people who have full citizenship of the following countries: Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, and the United Kingdom.

It should be noted however that in some cases holding a passport of an EU member state may not necessarily make you a full citizen of that country. An example of this are British Crown Dependencies such as the Isle of Man and the Channel Islands. People from crown dependencies travel with British passports but are not actually full EU citizens. This is reflected in the passport by the addition of a statement specifically excluding them from EU citizenship.