AutoIt began life as a scripting tool for installation programs, and has been expanded and enhanced to become a general purpose automation tool for Windows. With it, a skilled user with programming experience can write complex scripts to automate processes from file management to document creation. It is a powerful tool, but not one for novices.
Unlike many programming tools today, there is no IDE (Integrated Development Environment) or graphical interface builder. If you wish a GUI for your script, you must code it the old fashioned way, in plain text. There isn't even an event handler model; the program requires the developer to write an actual event loop. (If terms like 'event loop' are gibberish to you, this probably isn't the tool for you.) AutoIt includes a fully featured text editor included, and the ability to easily integrate with other popular editors. There's no smooth launch into a comfortable design environment here; after installing, a user must open the Help file and dig out the tutorials to begin learning the program. (It should be noted one of the example programs failed to run properly on my system, but the other three I entered and executed ran properly.)
However, the upside to this is programming power. AutoIt is capable of doing almost anything you might imagine to your system, including, of course, very bad things. AutoIt has a full suite of file and registry management functions, which are very useful in skilled hands and very risky for the incautious. From a programming perspective, it has all the control structures one might want. The syntax is very BASIC-like, with DIM statements, "$var" variable names, and loose typing: "10"+"20"=30, for example. GOTO, however, is entirely absent.
AutoIt is not designed for general purpose applications, Web back ends, or the like; it is a scripting tool for Windows automation, and the function list indicates it can handle almost any task in that field.