By creating an account, you'll be able to easily manage your Play Kits Subscription, review your order history, reschedule shipments, view upcoming Play Kits, and browse your Subscriber Shop. You also need an account to access The Lovevery App (that's full of parenting support) and view any Course Packs and any part(s) of the Reading Skill Set you may have purchased.
If you have a Play Kits Subscription and haven't created an account yet, you'll need to finish setting it up and verify your email the first time you log in. You can read more about account creation here.