To get the actual game files (the "WAD") for use with modern ports:
The most accessible way to download the game is via Steam or GOG . Download Doom 64
If you are looking for physical documents to accompany a download: To get the actual game files (the "WAD")
High-quality posters and box art can be found on marketplaces like Etsy for physical decoration. Download Doom 64
If you have an original ROM, you can use tools like Wadgen.exe to extract the data for use with high-performance fan ports like Doom 64 EX+ available on GitHub . Doom 64 pinky model update completed - Facebook