Vapor pressure is measured when a liquid and its vapor are?

its boiling

The evaporation of the liquid by heating.

Yes, for most liquids, if not all, the greater the temperature, the greater the vapor pressure.

They are the same when the air is saturated and the relative humidity is 100 percent.

This temperature is called the boiling point, and indicates the temperature at which a liquid will assume a gaseous state, given the addition of the heat of vaporization.