Hi Livizy,
If she's on an old enough iOS version she may need to update to be able to use some iCloud features. If she's out of space to do so, she can use a Mac or PC to bypass the internal storage on the iPhone.
After updating, if she still doesn't have access, have her follow the tips below to ensure she doesn't need to manually swap over from a personal iCloud+ plan.
"Switch from your personal iCloud+ plan to your family plan
When you share iCloud+, any family members using the free 5GB plan are added to your family plan automatically.
If a family member is already paying for their own iCloud+ plan, they can choose to switch to your plan or keep their own and still remain part of the family. When they switch to the shared family plan, they get a refund for the remainder of their personal plan. They can't keep their current plan and use the shared family plan at the same time.
On your iPhone, iPad, or iPod touch
In iOS 16 or iPadOS 16 later:
- Go to Settings > Family.
- Tap Subscriptions.
- Tap iCloud+.
- Tap Use Family Storage.
In iOS 15 or iPadOS 15 or earlier:
- Go to Settings > [your name].
- Tap Family Sharing, then tap iCloud+.
- Tap Use Family Storage. "
Take care.
