The existing Russian corpora do not yet provide opportunities for a systematic analysis of the language of official documents. There are few such texts in existing corpora. Moreover, there are the problems of genre classification and markup of non-fiction (incl. official, legal) texts. The paper describes the initial stage of the creation of the corpus of Russian internal documents and acts of CorRIDA. In everyday life, Russian speakers are increasingly faced with the need to read and sign various official documents. Usually these are so-called internal Documents, for example, Contracts or Consents. However, the language of such documents has not been examined with the use of corpus methodology. The corpus contains 1.5 million words, includes documents belonging to three socially significant domains (health, education, culture) and will allow the description of internal documents of various genres.