Quotation Marks
Quotation MarksDespite what you may see practiced—especially in advertising, on television, and even in business letters—the fact is that the period and comma go inside the quotation marks all of the time. Confusion arises because the British system is different, and the American system may automatically look wrong to you, but it is simply one of the frequently broken rules of written English in America: the period and comma go inside the quotation marks.
However, the semicolon, colon, dash, question mark, and exclamation point fall outside the quotation marks (unless, of course, the quoted material has internal punctuation of its own).
Self-Study
More advice on quotation marks, including conventions for using them with direct and indirect quotations, is available online at:
Advice on using quotation marks from Purdue's Online Writing Lab (OWL)
Quotation marks video from Sparkle English