Proofreaders' marks or, as they are often called "proofreading symbols", are still used, but with much less frequency than in the past. The advent of the Internet and word processing programs such as Microsoft Word and WordPerfect with their editing functions have made these proofreaders' marks almost obsolete. However, for those who do not like on screen editing and for those who must edit the hardcopy, these marks are still indispensable. The following is a complete list as taken from the Merriam-Webster dictionary. Local, in-house style guides may vary from company to company with additional marks specific to that industry but the proofreading symbols below are common to all. If you wish to be an all-encompassing editor or proofreader, ready for any situation, you should know these proofreaders' marks and be able to use them with ease.
delete and close up
insert a space
separates proofreader marks. Is also used as a final stroke after and insertion