<div class="form-group col-md-6">
                                <label id="input_label" for="address">Via / Corso / Piazza*</label>
                                <input type="text" class="form-control campi" id="address" required [(ngModel)]="registration.address" #address="ngForm" ngControl="address" [class.is-valid]="address.valid" [class.is-invalid]="!address.valid">
                            </div>