Copy editing encompasses mechanics like spelling, grammar, and punctuation.
This process aims to produce the most readable manuscript
by correcting outright mistakes and inconsistencies.
Line editing is a particular type of copy editing that focuses mostly on style.
This process takes much longer, as it has to do with the more
interpretive aspects of your story that could use a bit of finessing.
Examples of what I look for while copy and line editing:
Spelling and proper word usage
Compound sentence commas
Plurals and possessives
Word choices and overuse
Plot, character, scene, and detail consistency (red or silver car,
mom’s name, color of room, etc.)
Showing vs. Telling (body language during an argument, how the street looks, and how the weather feels on the way
home, where certain body parts are located during a steamy scene, and what character
is thinking about and physically experiencing in that moment, etc.).
And much more...
Line and copy editing will begin when you finish your final draft and will
always take place after content editing.