The Editor's Manual
Grammar, usage, punctuation, and style resource for editors, writers, and learners of the English language.
Useful tips for editors to edit better, impress and retain clients, and acquire new ones.
A style manual lists a set of standards for writing and editing documents. The AP Stylebook is most commonly followed in US journalism and corporate communication. Other major style guides are the Chicago Manual of Style, the APA Publication Manual, the New Oxford Style Manual, etc.
Freelance editors and proofreaders can work online for companies that provide editing services to businesses, students, writers, and others.