It is possible to message to and from the watch but not as SMS (text messaging) as you would on your cell phone. This is disabled for your child's protection. It can be activated in the parent app under SMS Messages, but its not suggested since spam and other types of messages can arrive.
Messaging with the Angel Watch is designed to work securely through the Angel Watch app using the Chat feature. This allows for voice & picture messages to go back and forth between the Angel Watch and the app. It is possible to send text messages from your phone, which has a full keyboard, but not from the watch to your phone as the screen is too small for practically typing letter by letter. The watch can respond to your text with one-press voice messages back.
There are occasions where you would want SMS messages to come through, particularly for receiving verification messages; as would be necessary to activate the messaging app on the watch called WhatsApp.
Any incoming SMS can be intercepted by activating text message receiving in the app's SMS Messages feature.
This is where your verification code for WhatsApp would arrive for example.
This app (similar to Skype) allows for any contact using their WhatsApp app to send text, voice & picture messages, all outside of the Angel Watch app.
This prohibits any sensitive access to the watch's more private information that's shared with app Family Members such as tracking, remote audio drop-in (Sound Guardian), and the ability to change the phonebook or other watch settings.
While Angel Watch app Chat messages are shared as family group messages, these apps allow for direct person-to-person communication.
WhatsApp can be installed from your watch's app store and downloaded for free onto just about any device.