In this manuscript, the stages of processing unstructured text data and the process of extracting knowledge based on them is studied. It is shown that the analysis of textual data is carried out in five main stages consisting of text identification, preliminary processing, knowledge building, application of Text Mining methods, and visualization of the results. Detailed information is provided on the operations performed at each stage and the technologies that are utilized. In the course of the research, models and algorithms for optimizing the processes of processing text data were developed. In particular, the mechanisms of text classification, emotional analysis, sentence structure determination, and analysis of texts on social networks are considered separately.