In the Object settings area, you first set how high the maximum age of a particle should be. You can enter a simple value, but a range of values and setting via curves is also possible.

Setting this value is the basis for all other settings that define the behavior over the lifetime. If this value is not set, all settings regarding the lifetime have no effect.

In the Particle life section you can define how a particle behaves over its lifetime.

You can influence one or more values here. It makes sense to define the settings as a curve.

For example, if you want a particle to fade in and out smoothly, create a curve with four points that describes an upward slope and a downward slope after a certain dwell time.

The meaning of the individual options is explained in more detail in the "Particles" chapter.