In addition to the ducal title, the dukes of Norfolk also hold the hereditary position of Earl Marshal, which has the duty of organizing state occasions such as the coronation of the monarch and the state opening of Parliament. For the last five centuries, save some periods when it was under attainder, both the dukedom and the earl-marshal ship have been in the hands of the Howard family. According to the House of Lords Act 1999, due to his duties as Earl Marshal, Norfolk is one of only two hereditary peers automatically admitted to the House of Lords, without being elected by the general body of hereditary peers (the other being the Lord Great Chamberlain).
Additionally, the Duke of Norfolk participates in the ceremony of the State Opening of Parliament. He is among the four individuals who precede the monarch, and one of the two of these who would traditionally walk facing the sovereign (thus backwards), but this has not been practiced in recent years.
As the Earl Marshal, the Duke of Norfolk is head of the College of Arms, through which he regulates all matters connected with armorial bearings and standards, in addition to controlling the arrangements for state functions. He is one of three claimants to the title of Chief Butler of England.
credit to encylopedia britannica for the anwser