Public domain – Public domain refers to creative works that are no longer protected by copyright law and are therefore free for use by the public without needing to obtain permission or pay royalties. A musical work will typically enter the public domain after the end of the copyright term –  70 years after the death of the last surviving author. 

it is important to note that while the composition might be in the public domain, specific recordings of that composition might still be under copyright if they were made more recently (within the last 70 years). Therefore, using a public domain piece might require creating a new recording or ensuring that the recording itself is also in the public domain.