Charlton, who was a key figure in England's 1966 World Cup-winning team, died at the age of 86 on Saturday.
He helped United win the European Cup in 1968 and three English league titles as well as the FA Cup.
"Bobby was a legend - a giant not only for Manchester United, but for football.
We have to live it every day," Ten Hag told reporters ahead of Tuesday's home game against FC Copenhagen.
Asked about how United would deal with the emotions of the game, Ten Hag said: "We are professionals, it's our job.
Persons:
Diogo Dalot, Erik, Hag, Bobby Charlton, Carl Recine, Erik ten Hag, Bobby, Denis Law, George Best, Sir Bobby Charlton, Rasmus Hojlund, He's, Marcus Rashford, Aadi Nair, Christian Radnedge
Organizations:
Soccer Football, League, Manchester United Press Conference, Trafford Training Centre, Rights, Manchester United, Charlton, United, European, FA, FC Copenhagen, Champions League, Copenhagen, Galatasaray, Premier League, Brentford, Sheffield United, Thomson
Locations:
Manchester, Britain, Rights MANCHESTER, England, Old Trafford, Bengaluru