Quotation mark in LaTeX

I always hit shift+$\boxed{{"}\atop{'}}$ twice in MS Word for inserting the quotation mark. However, it doesn’t work in $\LaTeX$ anymore—you’d only found two right kind of quotation marks eventually.

The correct way is to hit $\boxed{{\sim}\atop{`}}$ or $\boxed{{"}\atop{'}}$twice.