" " means space. For example when you want to print 2 string variables separated with space :
std::string str1 = "Hello"; std::string str2 = "World"; std::cout << str1 <<" "<< str2;
If you are asking about
" in cout, it is used to print any text inside the double quotes.
std::cout << "Any Text";
Remember the space inside
" " also a text.