Most of the session data is collected automatically by the Yandex.Metrica tag. You can supplement it with your own data by transmitting session parameters. However, you may find that information about the users themselves is more useful than session statistics.
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 is shown in the User parameters report. You can use the data as dimension and segmentation conditions.