An author's purpose is often to persuade us that the way "most people" understand something is actually false. madrigal does this in his article by (4 points)

saying that christmas cards cannot possibly mean all the things people want them to

saying that christmas cards are on the decline because of social media

saying that burleigh is an interesting writer

saying that there will be humblebrags all year round

saying that Christmas cards are on the decline because of social media

an argumentative essay presents objectively a topic and its main characteristics. besides, it states all this information and facts by giving authentic and substantiated proof to the audience. by contrast, a persuasive text purpose is to convince the audience about some facts by presenting them according to his/her emotions and feelings. the main purpose of a persuasive text is to convince the audience to agree with the author´s opinion. on the other hand, in the argumentative essay, the author leads the writer to recognize his/her point of view as the correct one.

most likely you should find things like facts and important information to you understand. i hope this .