Despite widespread use of software for writing and publishing, there are some cases in which knowing traditional proofreading symbols is recommended or required. This is especially true in the publishing industry.
Below is a list of some commonly used proofreading symbols. However, keep in mind that different editors will use variations of these and/or others that are not listed here.
New paragraph here
This symbol denotes that the writer should begin a new paragraph wherever the symbol is placed. Particularly for pages containing extensive dialogue, starting a new paragraph is necessary to help the reader visually follow the flow of the narrative without the author implicitly stating who is speaking.
Delete; take out something
When a letter, word or clause should be deleted, the delete symbol is used and should be written over the element to be removed.
Close up space
A proofreader in the publishing industry will look at the "proof", or printed copy of the publication, to check for errors. If there are spaces too wide that need to be closed, this symbol is used.
Transpose elements
It's easy for a writer to accidentally put words in the wrong order, which is why this sign is used to show elements should be transposed (or switched around).
Insert whatever is written above or below the proofreading symbol
When content is to be inserted, use this symbol along with whatever element should be inserted above or below it.
Insert en dash
The en dash is wider than a hyphen but narrower than the em dash and should be used between dates.
Insert em dash
The em dash can take the place of commas, parentheses, or colons and is a highly versatile punctuation mark. Considered less formal than parentheses, a pair of em dashes can be used to draw attention to the text within them without disrupting the flow of the sentence.
Move left
This proofreading symbol means the the content should be moved left. Note that the symbol should be as long as the lines of content to be moved.
Move right
This symbol means that the content should be moved right. As with the above symbol, this one should be as long as the lines of content to be moved.
Make italics
In most style guides, italics are used for book titles and other published material. This symbol means to change the word(s) to italics.
Change to capital letter(s)
If a word should have a capital letter, or multiple capital letters, this symbol is used.
Align vertically
This symbol means the content should be aligned vertically.
Align horizontally
This symbol is used to note when content should be aligned horizontally.