I’m not expecting people would know the when’s and where’s. But how aware were they that something was building up? Did everyone read the paper the next day and find out?
It wouldn't have come as a surprise to most Americans or Britons. It was obvious to many Britons, who could see the influx of men and war material. Many American families had relatives who'd been sent Britain and could easily guess why so many GI had been deployed there.
But the exact date and location of the landings were closely guarded secrets. Before the landing, almost all military posts had been locked down and most troops were not told about the landings until shortly before the planned landings (which ended up being delayed due to weather).
Radio, newspaper, and word of mouth would have been the first serious news about the landings most civilians heard.