Question mark for direct questions
A direct question should be followed by a question mark.
Question mark for questions in a series
Questions in a series may be followed by question marks even when they are not complete sentences.
No question mark with polite questions
If a polite request is written in the form of a question, it may be followed by a period.
No question mark with indirect questions
Do not use a question mark after an indirect question, one that is reported rather than asked directly. Use a period instead.
Exercise:
End punctuation
Related topics:
Question marks with quotation marks
Indirect questions