: If you want to play for free legally, you can download the original 9-level shareware episode from the Doom Wiki Shared Files or play it directly in your web browser via emulation sites like DOS.Zone .
While the first episode of the original 1993 game was famously released as free shareware, the complete expanded edition known as The Ultimate Doom is a commercial product that must be purchased. Ultimate Doom Free Download
If you tell me what operating system you are using, I can guide you on how to get the classic shareware version running safely. : If you want to play for free
: You can buy the verified, complete version of the game digitally on established PC storefronts like Steam or GOG . : You can buy the verified, complete version
: To run the game smoothly on modern computers, players typically take the official data file (DOOM.WAD) from their purchased copy and run it using free, open-source community engines like GZDoom or Chocolate Doom.