I am looking to launch a new rewards program for the baby company I work for but I am having problems pulling in all the field data from the 'create account' page into Klaviyo. It only pulls in the customer firstname, surname, dob, account creation, email address and if they accept marketing - which is great but for some reason it doesn't pull in the child's name or dob when the form is submitted. I've even added script that Klaviyo provide so the fields will link with our custom properties, but still no luck.
How do I pull this data into the Klaviyo? and what is the best way to do it?