Can’t bind to ‘formControl’ since it isn’t a known property of ‘input’

This issue arises just because the ReactiveFormsModule was not included in imported array of your component module. So, include it there

Say my module: admin.module.ts

import {FormsModule, ReactiveFormsModule} from '@angular/forms';

declarations: [ProductsComponent, CategoriesComponent,
    CategoryModalComponent
  ],
imports: [
    CommonModule,
    AdminRoutingModule,
    RouterModule,
    FormsModule,ReactiveFormsModule
  ],

But you also need to make sure that Component name (in my case is CategoryModalComponent) is also present in declarations array where you want to use it.