How do I upgrade my child's iCloud storage and manage family member access?

If you're on a family account, then the total storage space is shared amongst all the family members.

That's not to say everyone gets access to everyone else's files, just that the total volume of space is available to anyone in the family.

In this case, if you subscribed to the 200GB plan, then that's 200GB to share between all family members.

There's no control (that I'm aware of) to limit specific family members to specific amounts of storage - e.g. you can't say that you want 100GB, your daughter to have 50GB, and your spouse to have the remaining 50GB.

> Q1) how do I just subscribe my child separately as when I try to re subscribing to 50gb it asks for payment card details (on hers phone) so do I out mine in her phone??

I'm not 100% certain, since I've never needed to, but there are options to purchase additional space under each account. I'd read this as logging into her Apple Account (on her device) and using Settings -> iCloud -> Storage. It doesn't matter who pays for it (which credit card), only that it's subscribed under the appropriate account.

I haven't verified that a family member account can add storage outside of the family, but it makes sense.

> Q2) why do all family member still show 200bg access?

Because storage subscriptions are monthly. When you opted for 200GB, you got 200GB through the end of the month. The available space won't decrease until next months' renewal date.