A writer may decide to make use of a phrase to convey a specific idea to his audience.
This refers to the intended goal of a writer with regards to a written text and what he wants to convey to the readers.
Hence, if a writer makes use of a given phrase, he means to show or convey a purpose that is usually used in tandem with context clues so that the meaning would not be lost on the readers.
Please note that your question is incomplete so I gave you a general overview to get a better understanding of the text.
Read more about text purpose here:
https://brainly.com/question/26123730