Library science is a science that studies the occurrence, development, organization and management of libraries and the laws of library work. Its purpose is to summarize the practical experience of library work and library cause, establish a scientific theoretical system of library science, promote the development of library cause, and improve the position and role of library in the progress of human society. Library science is a developing science. Modern library science combines scientific contents with various attributes. With the progress of society and science and technology, especially the increasing demand for information and document exchange, the research and application prospect of library science will be broader.
Archives science is a subject that explores the development law of archives, archives work and archives cause, and studies the theory, principles and methods of archives information resources management and development. Its application is helpful to improve the scientific level of archives management, develop and utilize archives information resources more effectively, and serve the progress of human society. With the development of the objective situation, archival work and career must be guided by scientific theory, so archival science came into being and developed.
If you really want to know the difference, it's simple. Go to your local library and archives.
I wonder if your question has anything to do with employment. Libraries are basically full-time institutions and require exams to enter. Archives are institutions and archives are civil servants.