All over the the internet, and especially on SE sites, I see the following construction in the titles of questions:
How to write a question?
How to make a widget?
How to add foo to bar?
After some digging, I was able to find this previously answered question: Is a question beginning with “How to” grammatically correct?
Both answers offer some insight, but I'm looking for details regarding the correctness of the "sentence" when it includes the question mark, something @Kris mentions briefly that I still don't understand. He offers the example:
I don't have the manual now. How to fix my computer?
and says this is a grammatical sentence since the bolded part is used in context. Is this really grammatical? Both @Barry England and @Kris agree that this phrasing shouldn't be used in formal writing, but I can't think of any situation where (as a native speaker) I would use this even in informal speech. I would never say to a friend:
How to turn on your TV?
All three examples I gave earlier seem perfectly acceptable as titles for instructional articles on the topics when the question mark is removed:
How to write a question
How to make a widget
How to add foo to bar
but I can't help feeling that something is off when I see these titles with a question mark at the end.
Shouldn't they be written like this instead?
How can I write a question?
How is a widget made?
How is foo added to bar?