HOW do you turn off family sharing?

See the following from Leave Family Sharing - Apple Support

Any family member over the age of 13* can remove themselves from a family group.

On your iPhone, iPad, or iPod touch:

1. Go to Settings > [your name] > Family Sharing. If you're using iOS 10.2 or earlier, go to Settings > iCloud > Family.
2. Tap [your name].
3. Tap Leave Family.
   

On your Mac:

1. Go to Apple menu > System Preferences > iCloud > Manage Family.
2. Click [your name].
3. Click the Remove (—) button in the bottom-left corner.
   

When you leave Family Sharing, you lose access to any shared purchases or services shared by the family group.

If you go to System Preferences/iCloud, is there an option to Manage Family that contains the option to Share Purchases. If so, can you turn that off?