Hey there kinga209,
Thanks for reaching out to Apple Support Communities. We're happy to provide some assistance.
Let's make sure all of the requirements to Share iCloud+ with your family are followed as outlined under the "Share iCloud+ with everyone in your family" section here:
Share iCloud+ with your family - Apple Support
To share iCloud+, you need iOS 11 or later, iPadOS, or macOS 10.13 High Sierra or later. For the best experience, make sure that your family members' devices meet these requirements, too.
Learn what to do if a family member already has iCloud+
On your iPhone, iPad, or iPod touch
In iOS 16 or iPadOS 16 or later:
If you haven't set up Family Sharing yet, set up Family Sharing.
1.Go to Settings > Family.
2.Tap Subscriptions.
3.Tap iCloud+.
4.Follow the steps to share your existing plan.
5.Use Messages to let any family members with an existing iCloud+ plan know that they can now switch to your shared iCloud+ plan.
In iOS 15 or iPadOS 15 or earlier:
1.If you haven't set up Family Sharing yet, set up Family Sharing.
2.Go to Settings > [your name].
3.Tap Family Sharing.
4.Tap iCloud+.
5.Follow the steps to share your existing plan.
6.Use Messages to let any family members with an existing iCloud+ plan know that they can now switch to your shared iCloud+ plan.
If these steps have already been followed, please reach out to Apple directly to investigate:
Get Support
Have a great day!