how to add child to family sharing on ios sierra?

For future clarity Sierra is MacOS, iOS ids for iPhones

I'd think if it's available in Sierra it'd be just like the High Sierra method here...

Set up Family Sharing - Apple Support

Set up Family Sharing

Family Sharing lets up to six members of your family share iTunes Store, App Store, and iBooks Store purchases, an Apple Music family membership, an iCloud storage plan, and more—all without sharing accounts. Your family can also share a photo album, family calendar, and the ability to help locate each others’ devices with Find My iPhone.

One adult—the family organizer—sets up Family Sharing, invites up to five people to join the family group, and agrees to pay for any iTunes Store, App Store, and iBooks Store purchases those family members initiate while part of the family group. The family organizer can also set up Family Sharing so that all subscribed members can share the same storage plan and everyone can back up their devices, share photos, and store files in iCloud. Family members each need their own Apple ID for iCloud. For a child too young to create an Apple ID, the family organizer can create one on the child’s behalf. For more information, see the Apple Support article Family Sharing.

If you already have a family group, see Manage the family you organized or Join a Family Sharing group.

To set up Family Sharing using an iOS device, see the Apple Support article Set up Family Sharing.

1. Choose Apple menu > System Preferences, then click iCloud.
2. Click Set Up Family, then follow the onscreen instructions.
3. Click the Add button , then do one of the following:

• Add someone who has an Apple ID: Enter the name or email address of the person you want to join the family, click Continue, then follow the onscreen instructions.
  • If the person you’re adding is nearby, they can simply enter their Apple ID and password. Otherwise, you can email the person an invitation to join.
• Create an Apple ID for a child: Select “Create an Apple ID for a child who doesn’t have an account,” click Continue, then follow the onscreen instructions.
  • To comply with child online privacy protection laws, you use the CVV, a verification code sent via SMS, or the security code from your payment method as part of providing your parental consent. If you have a different payment method on file, you’re asked to change it to a credit card, debit card, or Union Pay before you can continue.

1. To add another member, repeat step 3.
2. To select the apps and services that you want your family to share, click Apps & Service, then do any of the following:

• • Subscribe to Apple Music: When you subscribe to an Apple Music family membership, all family members get unlimited access to Apple Music automatically.
  • Buy iCloud Storage: Buy a 200 GB or 2 TB iCloud storage plan and your family members can share it with you. Family members can also choose to keep their own individual storage plans if they prefer.
  • Set up Purchase Sharing: Click Purchase Sharing, then select your options. Your family can share purchases from the iTunes Store, the App Store, and the iBooks Store so everyone has access to them. All purchases are made through the shared payment method you set up. You can change the account used to make purchases and decline to share your purchases with family members.
  • Set up Location Sharing: Click Location Sharing, then click Learn More to learn how to set up location sharing on all your devices. You can set up location sharing so that all family members can view each other’s locations in Find My Friends, Messages, and Find My iPhone.

1. Click Done.

Before purchases are available to all family members, each person must confirm the Apple ID they use to share iTunes Store, App Store, and iBooks Store purchases. You do this in iCloud preferences on a Mac or in Settings > [your name] > iCloud on an iOS device. For more information, see Share purchases with your family.