You can add family members under 18 in your account by first logging in as yourself, then navigating to the Family Management tab in your menu (click the circle with your initials to access the menu).
From there, you'll be able to add a new family member.
Follow the prompts in the chat to complete a short intake.
Once the new account has been created, you are able to go back to the Family Management menu to switch accounts -- select the account you'd like from the drop down menu.
Once logged in as the selected family member (the initials in the circle on the right will change)
Use the left hamburger (three horizontal lines) menu to choose Popular Apps > VaxYes
Click Get Yours to get started
Follow the prompts in the chat to complete your family member's VaxYes registration.