How many triggers must a function have?

Without a trigger, an Azure Function would never know when to execute, making it non-functional in the serverless, event-driven model.

An Azure Function is fundamentally an event-driven piece of code, and a trigger is the mechanism that defines the event that causes the function to execute; therefore, every function must have exactly one trigger. This trigger acts as the entry point, defining how the function is invoked.

While a function can have multiple input and output bindings, it can only have one trigger to initiate its execution.