Since you don't specify a work, I'll speak generally about how words and phrases evoke emotion in an audience.

First, know that writers are using appeals to pathos when they attempt to evoke emotion from their audiences. So, writers have to consider what their larger message is and who their audience consists of in order to construct their messages effectively -- this is true of fiction and nonfiction.

For example, if I'm writing a novel, and I want to heighten my readers' suspicion of a character, I will use adjectives that cast that character in a suspicious light, such as "sly" or "manipulative." I also will manipulate narrative structure, perhaps using narrative breaks to my advantage, cutting scenes and ending chapters at climactic moments to build suspense and curiosity about the character.

Nonfiction works similarly, with writers choosing to use evidence and examples to pull at their audiences' emotions. If I am writing a human interest story about someone seeking refugee status, and I want my readers to feel sympathy and empathy for the person, I will include information that paints them in a positive light, that establishes them as someone my readers can relate to, and that establishes they should be granted refugee status.

As a final example, consider the following two sentences. Pay attention to how the use of contrast words ("but" and "though"), and the arrangement of the information, yields different reactions to readers:

"Your performance on the end-of-year project is solid, but your public speaking skills are poor."

"Your performance on the end-of-year project is solid; your public speaking skills can be improved, though."

Notice the difference? Imagine you're the worker receiving these evaluations - which version will bother you the least?

Your question is broad, so I hope this response is helpful. Essentially, know that words can evoke an array of emotions, and every aspect of the written product, from word choice to narrative structure, contributes to this process.