This Arduino sketch enables serial communication to read user input from the Serial Monitor, including an integer, a floating-point number, and a string, and then echoes the input back.

README arduino_user_serial_input This module makes it easy to accept user input from the serial interface, displaying the input buffer in real time. Example: ...

The small Arduino UNO terminal sender program is made to transfer Serial terminal data to the ESP32 Serial terminal only. This sketch is also attached herewith for ready references.