How to type a normal quotation mark without auto-substitution? Many apps offer the option to turn off auto-substitution on quotation marks (") such as TextEdit, but many other apps do not have such settings, for example LibreOffice.

So how to type a normal quotation mark in those cases?
In OpenOffice and LibreOffice, you go to Format > AutoCorrect > AutoCorrect Options > Localized Options and uncheck the boxes for Replace under Single Quotes and Double Quotes.