Most of the session data is collected automatically by the Yandex.Metrica counter. You can supplement it with your own data by transmitting session parameters. However, you may find that you are not interested in session statistics, but in getting information about the users themselves.
Yandex.Metrica lets you set custom data, called user parameters. For user parameters, we recommend transmitting user traits that don't change from session to session and that don't contain personal data such as the user's name. For more information about the difference between session parameters and user parameters, see Processing and storing data.
The transmitted information can be shown in a report, or used in conditions for dimensions and segmentation.