Pi 5 to Pi 5 commuincation

Does anyone know how to pass data through 2 pi 5's? serial communication? I want one pi to send a specific signal through a wire to another pi ideally both these actions are done through python

you could use GPIO

Raspberry Pi 5 uses the serial port in the same way as any other Pi or Linux computer for that. And read https://forums.raspberrypi.com/viewtopic.php?t=105995 for general knowledge and https://www.waveshare.com/wiki/Raspberry_Pi_Tutorial_Series:_Serial for serial python knowledge