In the Honorverse, a ship utilized as a flagship which often have additional facilities for the use of the flag officer and their staff, including a flag bridge from which the fleet or echelon unit is directed.
A flagship's commanding officer is known as the flag captain.
Flagships in TRMN
Fleet Commanders select a flagship, commonly their home chapter, but they may transfer their flag to other ships in the fleet periodically.
Admiralty Order 1612-02: Flagship Selection by Flag Officers