The history of the box office
Launch library · evergreen read

The box office originated as a single physical point where patrons could purchase tickets directly ahead of a performance, evolving from simple ad hoc arrangements at a venue's own entrance into a genuinely dedicated, structured system as venues and audiences both grew considerably in scale over time.
Centralising ticket sales this way solved a genuine practical problem: preventing double selling of the same seat and giving venues an accurate, reliable count of expected attendance ahead of a show, which mattered enormously for planning staffing, seating and general logistics on the actual night itself.
The term itself has outlasted the specific physical booth many people originally associate with it, now referring broadly to ticket sales and revenue for an event regardless of whether a genuine physical counter exists at all. Digital systems have inherited both the function and, informally, the name. This becomes second nature after the first attempt, even for someone organising an event for the very first time.