Why is the Gettysburg address a primary document?

It's a primary source because it is what the exact wording was during the speech so it hasn't been altered unlike a secondary source which basically passes down the information but it's sort of like the game telephone-everytime it's passed down its not nessasarly the same word anymore making the first person to say it a primary source but the second one and after are secondsry sources

Because all the things that have happened in Gettysburg they want to keep it safe and known