C problems

main.c
#include "management.h"
int main(){
  int menu=1;
  while(menu>-1){
    printf("Insert choice: \n");
    printf("1) Add employee.\n");
    printf("2) List employees.\n");
    printf("3) Delete employees.\n");
    scanf("%d", &menu );
    switch (menu) {
      case 1:
        addEmployee();
        break;
      case 2:
        listEmployee();
        break;
      case 3:
        deleteEmployee();
        break;
      default:
        printf("Exiting..\n" );
    }
  }
  return 0;
}
##################################################àà
management.c
#include "management.h"
FILE *file = NULL;
employee *inizializeEmployee(){
  employee *new = (employee*)malloc(sizeof(employee));
  insertName(new->name);
  insertBirth(new->birthDate);
  insertDateOfEmployment(new->dateOfEmployment);
  new->salary=insertSalary();
  return new;
}

void addEmployee(){
  int choice=0;
  printf("Adding a new employee\n");
  employee *new=inizializeEmployee();
  printf("A new employee was addedd.\n");
  return;
}

void insertDateOfEmployment(char string[]){
  puts("Insert employee's date of employment with the following format: 'YYYY-MM-DD'");
  fgets(string,12,stdin);
  return;
}
void insertBirth(char string[]){
  puts("Insert employee's birth date with the following format: 'YYYY-MM-DD'");
    fgets(string,12,stdin);
  return;
}
void insertName(char string[]){
  puts("Insert employee's name with the following format: 'Surname Name'");
    fgets(string,50,stdin);
}
double insertSalary(){
  double salary=0;
  printf("Insert salary with the following format: '1234.00'\n");
  scanf("%lf",&salary);
  return salary;
}
###########################################
management.h

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <string.h>

typedef struct employee{
  char name[50];
  char birthDate[12];
  double salary;
  char dateOfEmployment[12];
}employee;

employee *inizializeEmployee();
void addEmployee();
void listEmployee();
void deleteEmployee();
void spacing();
void insertName(char []);
double insertSalary();
void insertBirth(char string[]);
void insertDateOfEmployment(char string[]);