The $display system task in Verilog is used for displaying messages and variable values during simulation. It allows for printing text and formatted data to the console output. The test module in the provided code uses $display to print messages for simulation control and monitoring. This task aids in debugging and verifying the functionality of the design by providing insights into signal values and simulation progress. The provided Verilog code showcases various uses of the $display system task within a test module. It starts by printing "Hello World!" to the console and demonstrates displaying strings, decimal, binary, and hexadecimal numbers. Additionally, it displays hierarchical names and handles time-related outputs, including the current simulation time. Moreover, it exemplifies printing long messages by concatenating strings and combining them with other data types for display. This code serves as a comprehensive illustration of the versatility of the $display system task for debugging and monitoring during Verilog simulation.