EU nationals do not require a visa to enter the Federal Republic of Germany.
Non-EU nationals, generally speaking all other foreigners, require a visa for stays in Germany. A visa is usually not required for visits of up to 90 days in an 180-day period for nationals of those countries for which the European Community has abolished the visa requirements.
After creating a ConfTool user account you will be able to retrieve a visa invitation letter that confirms your participation in the conference.
In any case, please check if a visa is needed before your departure to Germany.
For an overview on visa requirements please visit: