Anyone can open an adult HyperJar account from 16+
You and your child can both download the HyperJar App and sign up for the Adult accounts and order your cards for your separate accounts.
You can then use the Shared Jar feature to Share Jars with your child and choose what sharing permissions you give them, from unlimited permissions to paying-in only or spending up to a set limit.
To Share a Jar, tap on the Jar and then on Invite. You can then choose to Invite sharers from your Contacts list or someone nearby (if you both have your Bluetooth switched on) or use a QR code.