Incentives are external stimuli or rewards that motivate behavior. They can be positive (rewards) or negative (punishments).
This is motivation driven by external rewards or punishments. Like studying hard to get good grades, not necessarily because you love learning.
This involves adding something desirable to increase a behavior. For example, giving a child candy for doing their homework.
This involves removing something undesirable to increase a behavior. Like turning off an annoying alarm by getting out of bed in the morning.