There are three structural directives in angular
*ngIf  
[ngSwtich]
*ngFor1. *ngIf (with else) use to hide/show element using like if-else condition as shown below
In below example we add else condition in ngIf block and then use ng-template to display else condition
import { Component, OnInit } from '@angular/core';  
@Component({
  selector: 'app-test',
  template: `
  <h1> Welcome {{name}} </h1>
    <h2> myStatus variable value is {{myStatus}} </h2>
      
     <h3 *ngIf="myStatus ; else myElseBlock"> this is if block</h3>
     <ng-template #myElseBlock>
     <h3> this is Else  block</h3>
     <ng-template>
  `,
  styles: [`   `]
})
export class TestComponent implements OnInit {
  public name = "Amey Raut";  
  public myStatus = false;  
  constructor() { }
  ngOnInit() {
  } 
 
  
}