What is the purpose of a descriptive essay?
to portray a subject using vivid language
to give details about a personal experience
to express some thoughts or ideas to readers
to convince readers to accept a specific point of view
to provide information about a topic to readers.

Descriptive essay, from its root word or base word, describe, it portrays a subject using vivid language or adjectives. It describes an event, a story, a person, it may describe the whole context with imagery. It also actually gives vivid details about a personal experience. However, to convince a reader is a persuasive text. And, to provide information is informative essays. 

Tell her/ him the positives of running outside.tell her/hime ur personal experiences