node --version

npm  --version

npm install -g @angular/cli

ng new <projectname>

npm install @techiediaries/ngx-qrcode

import { NgxQRCodeModule } from '@techiediaries/ngx-qrcode'; 

@NgModule({
imports: [ NgxQRCodeModule ] Can be given

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
  
// This import is required to have QRCode generation
import { NgxQRCodeModule } from '@techiediaries/ngx-qrcode';
import { QRCodeAppRoutingModule } from './qrcodeapp-routing.module';
import { QRCodeAppComponent } from './qrcodeapp.component';
  
@NgModule({
  declarations: [
    QRCodeAppComponent
  ],
  imports: [
    BrowserModule,
    QRCodeAppRoutingModule,
    NgxQRCodeModule,  // This import is required for QRCode
    FormsModule
  ],
  providers: [],
  bootstrap: [QRCodeAppComponent]
})
export class QRCodeAppModule { }

import { Component } from '@angular/core';
import { NgxQrcodeElementTypes, NgxQrcodeErrorCorrectionLevels } 
        from '@techiediaries/ngx-qrcode';
@Component({
  selector: 'app-root',
  templateUrl: './qrcodeapp.component.html',
  styleUrls: ['./qrcodeapp.component.css']
})
  
export class AppComponent {
  title = 'angular10qrcodegeneration';
  
  // We can have Canvas/Img/Url as elementType
  elementType = NgxQrcodeElementTypes.URL;
  
  // We can have High/Low/Medium/Quartile
  correctionLevel = NgxQrcodeErrorCorrectionLevels.HIGH;
  
  // Need to specify the valid website address
  value = 'https://www.geeksforgeeks.com/';
}

<ngx-qrcode
  [elementType]="elementType"
  [errorCorrectionLevel]="correctionLevel"
  [value]="value"
  cssClass="qrcodeshadow"></ngx-qrcode>
<!-- value that you want to encode -->
<textarea [(ngModel)] = "value"></textarea>

/* You can add global styles to this file, 
and also import other style files */
.qrcodeshadow {
    display: flex;
    align-items: center;
    justify-content: center;
    filter: drop-shadow(15px 15px 15px #e42424);
    opacity: .5;
}
    
textarea {
    margin-top: 15px; 
    display: block;
    margin-left: auto;
    margin-right: auto;
    width: 400px;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    font-size: large;
    font-weight: bold;
    color: green;
    opacity: .5;
}

ng build (at the location where your package.json present)

ng serve  (at the location where your package.json present)