I need help, i connect arduino mega with esp8266 nodemcu and it returns like above

Do not post screenshot. Copy and the paste the code and serial monitor output with triple backticks at the beginning and ending. So that is displays properly.

Triple backticks look like ( ``` )

You should start by reading this post about what is required from you when you crate a new topic on the forum…

Pete.

Mega with esp8266 :scream: