If you are a citizen of a country belonging to the Schengen area and you are going to travel to another country that is also a member, you will not need a visa. However, if you come from third countries and you are going to travel to a country in the Schengen territory, you will have to obtain a short-term Schengen Visa (if your trip is 90 days or less). You have all the information in: «Preparing for the plane trip: tips and troubleshooting«.
You have all the information in: "Preparing for the plane trip: tips and troubleshooting".