I have a control module that accepts 8V PWM signals. My goal is to send a 500Hz PWM signal from an Arduino to an 8V PWM input on the control module. Looks like everything generated from the Arduino is 5V. Is there a way to generate an 8V PWM output or method of manipulating that signal to reach 8V?
I'd suggest you use a power-source that delivers you 8V. Your Arduino takes anything from 7-12V to power it and it regulates it down to 5V. But you still can access the 8V from the RAW pins. Use a MOSFET like D1703L to control the 8V with an 5V Arduino digital pin.
You just connect Drain (D) to GND and Source (S) to your RAW 8V (don't forget to put your device between the Source and RAW 8V). Your Arduino digital pin goes to Gate (G), but to not draw to much current from the pin you might want to use a resistor of roughly 1kΩ.
This is the safest way that also allows for much higher voltage and also current for up to a few amps.
You should not connect the PWM pin to Ground on your Arduino. But you have to connect both grounds together. I'm not sure where your 8V comes from so I made a sketch where the 8V is an external source and powers your device along with the MOSFET.