<div>
  <app-header></app-header>
  <router-outlet></router-outlet>
  <app-footer *ngIf="!userLoggedIn"></app-footer>
</div>
<p-toast [style]="{ marginTop: '80px' }" key="myToast"></p-toast>

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
  providers: [MessageService]
})
export class AppComponent implements OnInit, OnDestroy {

  constructor(
    private readonly messageService: MessageService
  ) {...

this.messageService.add({
    severity: 'success',
    summary: 'Success Message',
    key: 'myToast',
    detail: 'Order submitted'
  });

this.ngZone.run(() => {
  this.messageService.add({
    severity: 'success',
    summary: 'Success Message',
    key: 'myToast',
    detail: 'Order submitted'
  });
});

setTimeout(() => {
  this.messageService.add({
    severity: 'success',
    summary: 'Success Message',
    key: 'myToast',
    detail: 'Order submitted'
  });
}, 1000);