If I get the 200GB option and share with my family then will all of them get 200GB or is the 200gb shared with the family numbers
The total amount the Family Sharing group can access is 200GB. This is available to everyone, not just the person who bought and/or paid for it.
But it's only 200GB, not 200GB multiplied by the number of family group members.
Use iCloud+ with your family
With Family Sharing, everyone in your Family Sharing group can share an iCloud+ plan, including premium features and all the storage you need with a single subscription.