LIke this:

Prosecutor: “The defendant is charged with murder.”
Judge: “How do you plead?”
Defendant: “Not guilty, your honor.”
Judge: “Okay, the trial will begin on…”

In the US justice system the defendant is presumed innocent until they either plead guilty or the prosecution proves that they are guilty. That’s just how it works.

Pleading is essentially asking the defendant, “did you do it?”

Edit for those who want to skip the comment chain:

“Did you do it?”

Yes == Guilty

No == Not Guilty

Neither == No contest