I cannot access my App Store . I cannot download anything on my daughter iPad

You came to the forum from a support document regarding the App Store being disabled. If that is the case, then you need to follow the steps in that support document and contact Apple Support. You cannot fix that on your own.

My daughter cannot access the app store on her iphone and unable to download any apps, she is under the child - family sharing, have I done something while setting up? We want to be able to access the app and download

You may have setup Parental Controls and or restricted access.

This link may help you https://support.apple.com/en-au/families-and-kids

I cannot access my App Store . I cannot download anything

And what happens when you try to access your App Store and you try to download something? You need to provide details to get assistance.