As opposed to football, a tennis Referee is not an “on-court official”.
The Referee assures that the competition is fair and played following the rules and regulation related to that competition.
The Referee supervises all aspects of play during a competition including the conduct of players, coaches, spectators, etc.
Where the Chair Umpire has the final say on issues relating to facts, the Referee ensures the rules of tennis are properly enforced and acts as the final authority on all questions relating on Tennis Law. For instance when it is the player’s opinion that the chair umpire misinterprets a rule, they have the right to appeal to the Referee.
Referee’s duties also include, but are not limited to, the making of the draw according to the competition’s regulations and the scheduling of the matches to be played.
(Stefan Fransson (SWE) conducts the draw for the Davis Cup Final)
The Chief Umpire is a “liaison officer” between the officials and the tournament staff and/or referee.
They coordinate the officials, assign the chair umpires and line umpires and deal with officiating problems or requests from officials.
Chief umpires are not required at every event but when present, they are a true asset for the good working of officiating at an event.
Further detailed information is outlined in the 'ITF Duties and Procedures for Officials', which is available as a PDF below.