Strings are declared in double quotes. AppleScript makes use of few symbols to understand exactly what the programmer is trying to script.
set emptyString to "" set spaceString to " " set hello to "Hello World"
Explanation: This will create 3 strings. First an empty String which contains nothing. Second a string which contains just a space and third a string which contains Hello World. Result tab will print Hello World
Figure 5.1.1 Output of String