WhatsApp is developing scheduled messages for iPhone, spotted in an iOS TestFlight beta. Users will pick a send time and manage queued texts.
So far, it's an inactive feature in the TestFlight beta version of WhatsApp for iOS, but it would let you pick a time and date for when a message is sent in the app.
WhatsApp is reportedly working on a native message scheduling feature that would let users compose a text, choose a specific date and time, and have it sent automatically.