Hi valeriaa_lavrova,
Re: "I am unable to leave Family Sharing Family Sharing I can't leave Family Sharing".
Your screenshot shows this is because your Family Sharing still has other members. As you are the organiser, it would no longer work for them if you were able to just leave. You have other options though.
Yoiu may want someone else to be the organiser now: See: Manage Family Sharing settings - Apple Support
Eg: Says:
“Note: The organiser can’t remove themselves from the Family Sharing group.
If you want to change the organiser, you must disband the group and have another adult create a new one”.
Also: The organiser can remove family members and disband the group.
_____________________________________________________________________________________________
More info, on leaving Family Sharing:
The article below can help you: "Learn the different ways you can leave or be removed from a family group and what happens when you stop using Family Sharing. If you're the family organizer, you can remove members at any time or disband the family group completely."
See how to:
Remove yourself from a family group
Remove someone from your family group
Disband a family group
What happens when you stop sharing?
See: Leave Family Sharing - Apple Support
All the best :-)