Send a string to Esp8266

Hi community :
I’m very VERY new in thinger.
I have an Esp8266 connected to Nextion display. It is connected to serial port.
Is there some way or commando to send a text to Esp8266 to store it into a buffer ?

I want to send a string from thinger.io to Esp8266, to show this message into display.

Many thanks in advance.

Omar