Set whatsapp to send delayed messages? Is there any extention or function to manage whatsapp to send delayed messages?

I would like to send every day a message at the same time but I do not find this function?

The message is different every day and there are images or text
There seems to be an app called Seebye Scheduler ROOT which can do what you intend but the device must be ROOTED and this one named Scheduler NO ROOT(from the same developer) is also available, for non-rooted device.

Once app is installed on your device, user needs to set a rule, by below steps,
 1. setting the user to whom the message will be sent, 2. message text that needs to be sent, 3. when it needs to be sent  4.how frequently it needs to be sent.

None of my devices are compatible with these app, hence I could not test it myself, but looks worth for trying! Good Luck.