<nav class="navbar navbar-inverse navbar-fixed-top">
  <div class="container">
    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar"
              aria-expanded="false" aria-controls="navbar">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>

    </div>

    <div id="navbar" class="collapse navbar-collapse">
      <ul class="nav navbar-nav navbar-left">
        <li><a class="navbar-brand" routerLink="/home">بستون</a></li>
      </ul>
      <ul class="nav navbar-nav ">
        <li><a routerLinkActive="active" routerLink="/home"><i class="fa fa-home fa-2x" aria-hidden="true"></i></a></li>
        <li><a routerLink="/about" routerLinkActive="active">درباره</a></li>
      </ul>
    </div><!--/.nav-collapse -->
  </div>
</nav>

<nav class="navbar navbar-inverse navbar-fixed-top">
  <div class="container">
    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar"
              aria-expanded="false" aria-controls="navbar">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>

    </div>

    <div id="navbar" class="collapse navbar-collapse">
      <ul class="nav navbar-nav navbar-left">
        <li><a class="navbar-brand" routerLink="/home">بستون</a></li>
      </ul>
      <ul class="nav navbar-nav ">
        <li><a routerLinkActive="active" routerLink="/home"><i class="fa fa-home fa-2x" aria-hidden="true"></i></a></li>
        <li><a routerLink="/about" routerLinkActive="active"><i class="fa fa-info-circle fa-2x" aria-hidden="true"></i></a></li>
      </ul>
    </div><!--/.nav-collapse -->
  </div>
</nav>

Change About Us text to A Item
Change About Us text to A Item
