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.