“Many authors don’t fully grasp the difference between a line edit and a copyedit. There are some similarities between the two: both pay detailed attention to your use of language, and involve mark-up on the pages of your manuscript. But make no mistake, these are two completely different processes, handled by professionals with different skill sets, and should occur at very different times during the writing process.
What’s a Line Edit?A line edit addresses the creative content, writing style, and language use at the sentence and paragraph level. But the purpose of a line edit is not to comb your manuscript for errors – rather, a line edit focuses on the way you use language to communicate your story to the reader. Is your language clear, fluid, and pleasurable to read? Does it convey a sense of atmosphere, emotion, and tone? Do the words you’ve chosen convey a precise meaning, or are you using broad generalizations and clichés?”
Source: What is the Difference Between Copyediting and Line Editing?