The proofreader uses a series of symbols and abbreviations to suggest changes, correct spelling errors, improve punctuation, and generally enhance the quality and readability of a hard copy document. Locating proofreading marks. In hard copy proofreading, corrections typically appear in the left or right margins beside the line containing the error. A mark is also placed in the text to indicate where the correction needs to be made. A caret (^) indicates an addition, and a line through the text indicates a deletion or a replacement. Proofreading marks are traditionally written in red ink for better visibility. Frequently used proofreading marks. Delete: , , or