You could move the functions to a singleton service and monitor the value using observables. Try the following

Shared service

import { BehaviorSubject, Observable } from 'rxjs';  // <-- included 'Observable' here - with capital 'O'

@Injectable()
export class SharedService {
  private addUsuarioSource = new BehaviorSubject<string>('false');
  public addUsuario$ = this.addUsuarioSource.asObservable();

  constructor() {
    this.addUsuario$.subscribe(status => window.localStorage.setItem('addUsuario', status));   // <-- changed 'userStatus' to 'status'
  }

  getAddUsuario(): Observable<string> {   // <-- capital 'O' instead of small 'o'
    let userStatus = window.localStorage.getItem('addUsuario');
    userStatus = (userStatus === 'false' || userStatus == null) ? 'true' : 'false';
    this.addUsuarioSource.next(userStatus);
    return this.addUsuario$;
  }
}

Navbar component

import { pipe } from 'rxjs';
import { map, take } from 'rxjs/operators';

export class NavbarComponent implements OnInit() {
  subscription: any;

  ngOnInit() {
    if (this.subscription) {
      this.subscription.unsubscribe();
    }
    this.subscription = this.sharedService.getAddUsuario().pipe(take(1)).subscribe(status => {
      // this callback will be called only once due to `pipe(take(1))`
      // `status` variable with value 'true' or 'false' as string
    });
  }
}

Another component

this.sharedService.addUsuario$.subscribe(status => {
  // this callback will be called each time a new user status is pushed
  // `status` variable with value 'true' or 'false' as string
})

I am using BehaviorSubject to provide a default value. You could use Rxjs Subject if you do not wish to provide a default value. Explanation for pipe(take(1)) can be found here.

Note: Storing boolean in local storage isn’t a good idea. Because you can only store strings and it returns the values as strings. So you cannot do something like *ngIf==="status" or *ngIf==="!status". It would be *ngIf="status === 'true'" and *ngIf="status === 'false'".

Working example: Stackblitz

You can do this in your typescript

create a global variable like this:

addUsuario:boolean;

getAddUsuario(){ 
if(window.localStorage.getItem('addUsuario') == 'false'){
window.localStorage.setItem('addUsuario','true');
//and do this one
addUsuario = true;
}else{
window.localStorage.setItem('addUsuario','false');    
addUsuario = false;  
}
return window.localStorage.getItem('addUsuario');

and in your HTML you can use *ngIf
for example:

<div *ngIf="addUsuario == true">
<!--Your div-->
</div>
<div *ngIf="addUsuario == false">
<!--your div-->
</div>

I have this funcion on the component calls navbar:

getAddUsuario(){
if(window.localStorage.getItem('addUsuario') == 'false'){
  window.localStorage.setItem('addUsuario','true');

}else{
  window.localStorage.setItem('addUsuario','false');      
}
return window.localStorage.getItem('addUsuario');

So, when i click the variable addUsuario change to false if is true and to true if is false.

The problem is i wqant to detect that changes from another component and pass it into HTML. if is true take a div class and if is false take another div class.

I tried with addEventlistener but doesnt work.

Thanks