Empty Chat is a prank app that lets you send empty messages in a WhatsApp conversation. Using this app is very easy as it does not involve difficult steps.
You only need to open this app on your phone and then select the contacts to whom you want to pull this prank. Now, tap on the send button and your message will be sent with no words.
You can download the APK file of Empty Chat from here and surprise your friends with a blank message on WhatsApp.