Data mining is used for finding the useful information from the large amount of data. Data mining techniques are used to implement and solve different types of research problems. The paper related areas in data mining are text mining, web mining, image mining, sequential pattern mining, spatial mining, medical mining, multimedia mining, structure mining and graph mining. This paper discussed about the text mining and its preprocessing techniques. Text mining is the process of mining the useful information from the text documents. It is also called Knowledge Discovery in Text (KDT) or knowledge of intelligent text analysis.