JavaScript strings are used for storing and manipulating text such as a series of characters like "John Doe". A string can be any text inside single or double quotes:
carName = "Volvo XC60";
var carname = 'Volvo XC60';
Quotes can be used inside a string, as long as they don't match the quotes surrounding the string:
var answer = "It's alright";
var answer = "He is called 'Johnny'";
var answer = 'He is called "Johnny"';