Information retrieval is a process that fulfills the need for information by using different kinds of sources of information. The information acquired has to be relevant and as comprehensive as possible considering the information needed.
Information search consists of looking for specific information from different information sources using different entries and search techniques. The knowledge of different information sources and search techniques helps the information retrieval a lot.
Information source can be for example a book, a paper, a database, a website or for instance a person.
Information management consists of a critical evaluation of the information, on the basis of a content and a source of the information that has been found. Information management also involves an orthodox use of the information.