How do I move or copy my individual iCloud data to a Family Sharing iCloud account

When you share an iCloud storage plan, you continue to store your own data under your own Apple ID in iCloud. You are just sharing the storage plan.

Also see information in Share iCloud+ with your family - Apple Support including the following:

When you share an iCloud+ subscription, everyone in the family group uses their own account. That way your photos, documents, and other information stay private, even though you're sharing access to the service. You simply share the features and space available in iCloud+ with your family members, so you only have one plan to manage.