String is the head of a character string "text".
Strings can contain any sequence of ordinary or special characters.
x_String can be used as a pattern that represents a string.
String is used as a tag to indicate strings in Read, terminated by RecordSeparators characters.
In InputForm, special characters in strings are given as \[Name] or \:code.
Except when they are enclosed between \< and \>, newlines and any tabs which follow them are ignored when strings are input.
See Section 2.8.1.
See also: ToExpression, ToString, SyntaxQ, Characters.
New in Version 1; modified in 3.