The legal and physical entities entrepreneurs carry out their activities within the framework of the law. Among other requirements, the activities (services, works, etc.) are classified according to individual types, and they are assigned the codes. Activities are recorded in the Classification of Economic Activities (CKEA, or in abbreviated form).
Any legal entity in the statutes is required to identify those activities which it actually carries out. An individual entrepreneur shall notify the service EDRPOU about activities which it carries out and the data are entered in EDRPOU. In the case of non-compliance activities or their absence, the entrepreneur or legal entity can be a problem, in the form of penalties, failure to issue licenses, permits, etc..
Description of the general procedure CKEA shift for legal entities (for example, LLC.) and individual entrepreneurs (SAP) can be found at the link: change of the main activities of the organization. The article also told other interesting questions.