onSubmit() {
    const fd = new FormData();
    fd.append('resume', this.chosenFile);
    const data = this.contactForm.value;
    data['resume'] = fd;
    console.log(data);
    this.loading = true;
    this.data.createJobEnquiry(data).subscribe((res)=>{
      this.loading = false;
    },(err)=>{
      this.loading = false;
      console.log(err)
      alert("Something went wrong");
    });
  }

onSubmit() {
    const fd = new FormData();
    fd.append('resume', this.chosenFile);
    const data = this.contactForm.value;
    data['resume'] = fd;
    console.log(data);
    this.loading = true;
    this.data.createJobEnquiry(fd).subscribe((res)=>{
      this.loading = false;
    },(err)=>{
      this.loading = false;
      console.log(err)
      alert("Something went wrong");
    });
  }

<input formControlName="resume" type="file" id="real-file" (change)="onFileSelected($event)" style="display: none;">

onFileSelected(event) {
  this.chosenFile = <File>event.target.files[0];
}