An electronic apparatus and a controlling method thereof are provided. The method of controlling an electronic apparatus according to an embodiment includes: obtaining first text information including a plurality of words, identifying a security level of the first text information based on at least one of a source from which the first text information is obtained or a type of the first text information, obtaining second text information by converting at least one of the plurality of words included in the first text information based on the identified security level, and obtaining first summary sentence information summarizing the second text information through a summary module.