The tournament, which gets underway at the end of October, is being hosted by England and Wales, with further matches played in Ireland and France.
"England need success in the tournament to make people across the country take notice," Charnley told BBC Sport.
"The World Cup is very exciting - especially because it is mainly going to be hosted in England. It's good for English rugby and hopefully we can get the whole country to back us.
"Winning the tournament would be massive in terms of promoting the game and boosting its profile nationwide."
England open the tournament on October 26 against Australia in Cardiff.