Reno is quite right here.
Power factor is the ratio of useful power(VxI) to useless (Wattless) power in a circuit or even an entire installation.
To a degree, the lower the wattless component, the higher the power factor.
It is about using the most from what you have supplied to you.
We had a dedicated PF meter at the PoCo, but I can't at this moment remember how it was wired.
What's even more scary, is the fact that I built the thing in the first place.
Let's face it, these days if you're not young, you're old - Red Green