Use an IOCTL to create a beep from Beep.sys

BeepDriverIOCTL.c

#include <Windows.h>
#include <stdio.h>
#include <winternl.h>

typedef struct _BEEP_SETTINGS {
	ULONG ulFrequency;
	ULONG ulDuration;
} BEEP_SETTINGS;

void main() {
	// Prep string
	UNICODE_STRING uszDeviceName;
	OBJECT_ATTRIBUTES BeepObjectAttributes;
	RtlInitUnicodeString(&uszDeviceName, L"\\Device\\Beep");
	// Prep object
	InitializeObjectAttributes(&BeepObjectAttributes, &uszDeviceName, 0, NULL, NULL);
	// Get a handle on beep.sys
	PIO_STATUS_BLOCK pOutStatus = 0; 
	HANDLE hDriver;
	IO_STATUS_BLOCK IoStatus;
	NTSTATUS ntOut = NtCreateFile(&hDriver, 0x3, &BeepObjectAttributes, &IoStatus, NULL, 0, 0x3, 0x3, 0, 0, 0);
	if (ntOut == 0x0) { 
		DWORD dwIOCTL_BEEP = CTL_CODE(FILE_DEVICE_BEEP, 0, METHOD_BUFFERED, FILE_ANY_ACCESS);
		BEEP_SETTINGS BeepSettings;
		BeepSettings.ulDuration = 10000;
		BeepSettings.ulFrequency = 500;
		DWORD dwReturned = 0; 
		DeviceIoControl(hDriver, dwIOCTL_BEEP, &BeepSettings, sizeof(BEEP_SETTINGS), NULL, 0, dwReturned, NULL);
	} // You should add an else statement
	ExitProcess(0);
}
// I know this is super useful, so you're welcome!

Reviewed code to work in Windows 11 (with VS 2022):

#include <Windows.h>
#include <stdio.h>
#include <winternl.h>

typedef struct _BEEP_SETTINGS {
	ULONG ulFrequency;
	ULONG ulDuration;
} BEEP_SETTINGS;

int main() {
	// Prep string
	UNICODE_STRING uszDeviceName;
	OBJECT_ATTRIBUTES BeepObjectAttributes;
	RtlInitUnicodeString(&uszDeviceName, L"\\Device\\Beep");

	// Prep object
	InitializeObjectAttributes(&BeepObjectAttributes, &uszDeviceName, 0, NULL, NULL);

	// Get a handle on beep.sys
	HANDLE hDriver;
	IO_STATUS_BLOCK IoStatus;
	// Added GENERIC_READ | GENERIC_WRITE
	NTSTATUS ntOut = NtCreateFile(&hDriver, GENERIC_READ | GENERIC_WRITE, &BeepObjectAttributes, &IoStatus, NULL, 0, 0x3, 0x3, 0, 0, 0);
	if (ntOut == 0x0) {
		BEEP_SETTINGS BeepSettings;
		BeepSettings.ulDuration = 1000;
		BeepSettings.ulFrequency = 500;
		DWORD dwReturned = 0;
		DWORD dwIOCTL_BEEP = CTL_CODE(FILE_DEVICE_BEEP, 0, METHOD_BUFFERED, FILE_ANY_ACCESS);
		BOOL result = DeviceIoControl(hDriver, dwIOCTL_BEEP, &BeepSettings, sizeof(BEEP_SETTINGS), NULL, 0, &dwReturned, NULL);
		if (!result) {
			printf("Error in DeviceIoControl: %d\n", GetLastError());
			CloseHandle(hDriver);
			return 1;
		}
		
		Sleep(BeepSettings.ulDuration); // We need to delay the close of the handle until the beep is done
		CloseHandle(hDriver);
	} else {
		printf("Error in NtCreateFile\n");
	}
	
	return 0;
}