Writers use quotation marks primarily to enclose direct quotations of another person’s spoken or written words. You will also find these other uses and exceptions:
for quotations within quotations (single quotation marks: P5-b)
for titles of short works (P5-c)
for words used as words (P5-d)
with other marks of punctuation (P5-e)
with brackets and ellipsis marks (P6-b, P6-c)
no quotation marks for indirect quotations, paraphrases, and summaries (P5-a)