While you may find "free download" links for Final Fantasy XV Windows Edition on unofficial sites, these are generally pirated versions that carry security risks like malware.
The only legitimate way to play for free is through the or specific editions with free initial content: FINAL FANTASY XV WINDOWS EDITION Free Download ...
: A stylized version of the game where Chapter 1 is free to download and play, with subsequent chapters available for purchase. Where to Buy Officially While you may find "free download" links for