Hello @Krzysztof Pabian
Do you mean the Machine-ID for the Refinitiv Real-Time - Optimized (RTO) connection? If so, did you receive the Welcome email from the system? The Machine-ID information is available in the Welcome email.
Once you have the Welcome email, you can follow through with the steps in "Getting Started for Machine ID" section of the Getting Start with Refinitiv Data Platform article.