Apple provides extensive support and details regarding these features. Basically, the Family Sharing can be enabled from any compatible iOS device or from the Mac.
For the iPhone, iPad, or iPod do the following: Go to Settings > iCloud and tap on Set Up Family Sharing then get Started. Confirm the selection and regarding family organizer and that you're signed with your Apple ID, then follow the on-screen instructions.
For Mac: Go to Apple menu > System Preferences, then click iCloud. Click Set up Family on the left and follow the on-screen instructions.
To invite people:
iPhone, iPad, or iPod touch: Settings > iCloud > Family > Add Family Member. (enter family member's name or email address and follow the instructions)
Mac: Apple menu > System Preferences, then click iCloud. (click Manage Family then click on + sign and follow the instructions)
For additional information, check the pages below:
