How to Send Invisible Ink Messages from iPhone and iPad
iOS Messages includes the Invisible Ink feature which allows people to send obfuscated messages to and from iPhone and iPad. The invisible messages arrive visibly obscured, and the content of the invisible message can only be revealed by swiping a finger on the blurred message(s) to temporarily reveal the message text, image, or video. And yes, that means invisible messages can send not just as invisible text, but also as invisible photos and invisible videos too.
Invisible Ink offers simple privacy in a fun way to share secrets or otherwise personal information through the Messages app of iOS without having them be visible to an onlooker. The feature is part of the Message Effects set and is available on releases of iOS for iPhone, iPad, and iPod touch.