How to set up iCloud sharing in iPhone?
I have purchased the family sharing and invited my wife and the iCloud drive is not available to share in her iPhone.
iCloud Drive FAQ - https://support.apple.com/HT201104 - iCloud Drive lets you securely access all of your documents from your iPhone, iPad, iPod touch, Mac, and Windows PC.
Set up iCloud Drive - https://support.apple.com/HT204025