As detailed in the Guidelines on Open Access to Scientific Publications and Research Data in Horizon 2020, it is a good idea to add licenses for any datasets created. They should indicate how the data may be used.
Public Domain Dedication and License (PDDL)“Public Domain for data/databases” allows you to freely share, modify and use work for any purpose, and without any restrictions
Attribution License (ODC-By)“Attribution for data/databases” allows third parties to copy, distribute and use the database, as well as use it to create new content, databases or groups of databases (provided the original database is cited)
Open Database License (ODC-ODbL)“Attribution Share-Alike for data/databases” allows third parties to copy, distribute and use a database, as well as use it to create new content, databases or groups of databases, provided the derivative databases are given the same license as the original database.