Ethos, also known as Appeal to Authority, is used to convince an audience based on the author's credibility or character.
Logos, sometimes known as Appeal to Logic, is used to persuade people with a reason, logic, and facts.
Pathos, also known as Appeal to Emotion, plays on the emotions of the audience to persuade them. It is also used when you want the audience to feel something towards you; want to leave a mark on them.