What " means
They enclose quotations, titles, or words singled out for discussion. In English writing, double quotes can mark dialogue, song or article titles, and a word treated as a word rather than used for its meaning.
Around a label, they become scare quotes: punctuation that signals doubt or irony. Calling advice "helpful" may repeat someone's description, or suggest it was anything but. If you only mean emphasis, skip the quotes. If someone sends them to you, read the whole sentence before assuming a sneer.
Should I use straight or curly quotes?
Straight for code; curly for typeset prose. Programming languages and data formats such as JSON require this exact straight character. Follow their syntax rather than swapping in a prettier mark.
Smart punctuation in word processors and phone keyboards turns straight quotes into separate opening and closing characters. Which pair you get depends on the language setting, so it is a character change, not a font change. Turn that conversion off when you need literal straight quotes.
Neutral around borrowed words; potentially barbed around a person's label.
Scare quotes can turn intended emphasis into sarcasm.
Don't confuse it with
2Questions people ask
1Why does " show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type "
"\0022Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.