A lot of different countries have different quotation marks. Starting this list will be the USA with "Words". Then comes the britians with their 'Words'. The Germans then mainly use ,,Wörter" and rarely >>Wörter<<. French use it the other way around with <
Commas and periods need to be in the quotation marks. Question marks and exclamation points should only be inside if they were a part of the quote.
Quotation marks can be used to communicate irony. Writing a book is very "easy".