The original version of "Amazing Grace" was written by John Newton in the 18th century. However, Newton never copyrighted the hymn, and it has since been published in numerous hymnals and other publications without any copyright restrictions. As a result, it is now considered to be in the public domain.
It's important to note that while the lyrics of "Amazing Grace" are in the public domain, specific arrangements or recordings of the hymn may be subject to copyright protection. For example, a particular musical arrangement or performance of "Amazing Grace" could be copyrighted by the musician or recording artist who created it. In these cases, you would need to obtain permission from the copyright holder before using or distributing the copyrighted material.