From Solution Explorer, open the app.module.shared.ts file and add the following (new lines are highlighted):
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
[...]
imports: [
CommonModule,
HttpClientModule,
FormsModule,
ReactiveFormsModule,
[...]
That's it, now we're good to go.