Similar to how you can two-way bind [(ngModel)] you can two-way bind custom property on a component, for example [(value)]. To do it use appropriate Input/Output naming:

@Component({
      selector: 'super-input', 
      template: `...`,
    })
    export class AppComponent {
      @Input() value: string;
      @Output() valueChange = new EventEmitter<string>();
    }
    

Then you can use it as:

<super-input [(value)]="value"></super-input>