If you want to add an e-book to your child’s Freetime account, it’s more complicated than delivering it to the device after you buy it. I cannot find any documentation, so this is how I did it:
- Visit www.amazon.com. Log in if you haven’t already.
- Hover over Accounts & Lists and select Your Content and Devices.
- Click Show Family Library.
- Place a checkmark next to all books you want to share with your child’s Freetime account.
- Click Add to Library.
- At the bottom of the Add to Library dialog, select the child you want to have the books.
- Press OK.
(EDIT (2020-08-07): This paragraph may be an unnecessary step. Let me know in the comments.) After that, you then need to pick up your kid’s device and exit Freetime. Restart Freetime, and when you do so, you’ll check the box for the book you just purchased.