Where can I find Siri's file, folders, database in ios files (I'm root)
There's not just some file you can just go edit for the "Hey, Siri..." phrase. There are localized language files for Assistant (Siri) and the rest of iOS that contain information about what certain words and language in general looks like to a computer. I'm fairly certain that these files are located at /System/Library/LinguisticData/. There are people who have modified the "Hey, Siri..." phrase before, so it's not impossible, but it's not just a simple edit of some .plist somewhere.