It was said that the initial French charge was met by 75,000 arrows in one minute. The archers must have had to release one arrow before the previous one landed. They didn’t need much accuracy, they were firing into a mass of horsemen. A horse struck by an arrow became uncontrollable, some turned around and drove into masses of French men-at-arms following behind the cavalry. The longbow was employed by both sides at Agincourt, but the French bowmen were said not to have played much of a role.
I think the French were dominated by crossbowmen, who they left behind in the initial attack.
I just did the calculations. At 170fps initial release, a warbow at 45 degrees would shoot nearly 300m but take 7.5s to reach the target. That is plenty of time for a 2nd shot.