When creating content, it is vital to understanding what copyright is and how it applies to you. Any piece of work you create is automatically covered by copyright laws. Meaning that If you released a song, for example, someone couldn’t take the same song and use it without permission.
This being said, if someone took part of your song to critique or make a parody as an example, even to work you haven’t given permission for others to use, they have not broken any copyright laws as it is considered fair use.
by definition: “fair use is any copying of copyrighted material done for a limited and “transformative” purpose, such as to comment upon, criticize, or parody a copyrighted work.”
Additionally, If your work is in the Public Domain, it may also be used without permission. works in the public domain are those whose exclusive intellectual property rights have expired, have been forfeited, or are inapplicable.