If a music is in the public domain, it can be used by anyone for any purpose, without obtaining prior permission.
Duke's Center for the Study of Public Domain has a list of musical compositions that are entering public domain this year.
Please note: The websites below contain public domain resources but may also have content that is under copyright. If you need help verifying whether something is public domain, or have questions about how to use and cite images, please Ask a Librarian – we’re here to help!