They are placed outside of the quotation marks.
It depends where you live. In the USA punctuation is placed inside the quotes, like this: "My dog is brown." but in Britain, it is placed outside the quotation marks, like this "My dog is brown".
Punctuation marks such as periods and commas should be placed outside the set of quotation marks. Question marks and exclamation points should be placed inside if they are part of the quoted material, and outside if they are not.
In American English, periods and commas are typically placed inside final quotation marks, while colons and semicolons are placed outside.
The same punctuation is used inside of quotation marks as is used outside of quotation marks.
In American English, an exclamation point should be placed inside quotation marks, followed by a comma if necessary: He shouted, "Stop!" In British English, the exclamation point would be placed outside of the quotation marks: He shouted, "Stop"!
In American English, periods and commas should always be placed inside the set of quotation marks. Question marks and semicolons are placed inside the quotation marks when they belong to the quoted material but outside when they apply to the whole sentence.
The quotation marks are placed at each end. In other words, the question mark should be inside the quotation marks.
The comma is inside the quotation mark if it is part of the quote. For example: John said, "Please pass the butter, and then could you pour me some milk?" Notice that there is also a comma after the word "said" that is not in quotation marks. This is because "said" is not a part of the quote. Be careful of indirect quotes which do not use quotation marks, such as: John said to please pass the butter and then pour him some milk. An easy mistake is to write: John said "to please pass the butter and then pour him some milk" which would be incorrect since that is not what John said.
In dialogue, periods, commas, question marks, and exclamation points go inside quotation marks. (A semicolon goes outside quotation marks but isn't used much in dialogue, so you don't need to worry about it.)
In American English, periods are typically placed inside quotation marks at the end of a sentence. However, in British English, the period is placed outside the quotation marks unless it is part of the quoted material.
British style places commas and periods that are not part of the quoted material outside of the quotation marks. Also, in technical applications or when discussing coding, punctuation that is not part of a text string should be placed outside of the quotes. Placing commas and periods inside the quotes implies that they are part of the string to be displayed.
Yes, in American English, periods are placed inside quotation marks.