These are some of the most common used signs for proofreading.

sign	explanation	examples
	Lower case.
	Upper case.
	Check original or ask author.
	Boldface.
	Join lines.
	Separate lines.
	Italics.
	Delete (deleátur).
	Omission.
	New paragraph.
	Change letters.
	Callings are placed over the letter or word that must be corrected. In addition, they are placed also at the margin, with the appropriate sign of correction.