WhatsApp - a guide for parents and carers
What is WhatsApp?
Does WhatsApp have any age restrictions?
If WhatsApp learns that identifiable information of a child under 16 has been collected on the WhatsApp Site or WhatsApp Service, then WhatsApp may deactivate the account.
How much does it cost?
WhatsApp uses an Internet connection using 4G or Wi-Fi to send and receive messages to your contacts. As long as the user hasn’t exceeded the data limit or is connected to a free Wi-Fi network, messaging over WhatsApp should not cost extra.