Some fans have remade the Warcraft III experience in the StarCraft II engine (which is free-to-play). A notable project is Azeroth Reborn , which allows you to play through the original campaigns for free. How to Install Warcraft III (Official Method)
Download and install the Battle.net App. Warcraft III Free Download
Navigate to the "Games" section and find Warcraft III: Reforged . Some fans have remade the Warcraft III experience
If you still have your original Reign of Chaos and The Frozen Throne CD keys, you can link them to your Battle.net account to gain access to the "Classic" version within the modern launcher for free. Navigate to the "Games" section and find Warcraft
The short answer is of the full game released by Blizzard Entertainment. However, there are specific legal ways to access the game if you have previously owned it or if you use specific subscription services.