You cannot legally download the main game PAK files (like pak0.pak and pak1.pak ) for free, as they remain copyrighted material. To obtain them, you must purchase the game from a legitimate retailer:
To use Quake Pak files, follow these general steps: Quake Pak Files Download
Gone are the days of needing a CD-ROM drive. Today, you can legally obtain the contents of pak0.pak and pak1.pak through several digital distribution platforms. Each of these provides the necessary game data that your source port will read. You cannot legally download the main game PAK
For map makers and modders, understanding how to manipulate PAK files is essential. Quake Pak Files Download