To upload multiple files with angular form data, make sure you have this in your component.html
Upload Documents
                <div class="row">
                  <div class="col-md-4">
                       <small class="text-center">  Driver  Photo</small>
                    <div class="form-group">
                      <input  (change)="onFileSelected($event, 'profilepic')"  type="file" class="form-control" >
                    </div>
                  </div>
                  <div class="col-md-4">
                       <small> Driver ID</small>
                    <div class="form-group">
                      <input  (change)="onFileSelected($event, 'id')"  type="file" class="form-control" >
                    </div>
                  </div>
                  <div class="col-md-4">
                      <small>Driving Permit</small>
                    <div class="form-group">
                      <input type="file"  (change)="onFileSelected($event, 'drivingpermit')" class="form-control"  />
                    </div>
                  </div>
                </div>
                <div class="row">
                    <div class="col-md-6">
                         <small>Car Registration</small>
                      <div class="form-group">
                        <div class="input-group mb-4">
                            <input class="form-control" 
                (change)="onFileSelected($event, 'carregistration')" type="file"> <br>
                        </div>
                      </div>
                    </div>
                    <div class="col-md-6">
                        <small id="li"> Car Insurance</small>
                      <div class="form-group">
                        <div class="input-group mb-4">
                          <input class="form-control" (change)="onFileSelected($event, 
                         'insurancedocs')"   type="file">
                        </div>
                      </div>
                    </div>
                  </div>
                <div style="align-items:c" class="modal-footer">
                    <button type="button" class="btn btn-secondary" data- 
                  dismiss="modal">Close</button>
                    <button class="btn btn-primary"  (click)="uploadFiles()">Upload 
                  Files</button>
                  </div>
              </form>
In your componenet.ts file
declare array selected files like this
selectedFiles = [];
// array of selected files
onFileSelected(event, type) {
    this.selectedFiles.push({ type, file: event.target.files[0] });
  }
//in the upload files method, append your form data like this
uploadFiles() {
    const formData = new FormData(); 
    this.selectedFiles.forEach(file => {
      formData.append(file.type, file.file, file.file.name); 
    });
    formData.append("driverid", this.driverid);
    this.driverService.uploadDriverDetails(formData).subscribe(
      res => {
        console.log(res); 
      },
      error => console.log(error.message)
    );
  }
NOTE: I hope this solution works for you friends