Answers for "bootstrao drop down submenu"

dropdown bootstrap

<div class="dropdown show">
  <a class="btn btn-secondary dropdown-toggle" href="#" role="button" id="dropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    Dropdown link
  </a>

  <div class="dropdown-menu" aria-labelledby="dropdownMenuLink">
    <a class="dropdown-item" href="#">Action</a>
    <a class="dropdown-item" href="#">Another action</a>
    <a class="dropdown-item" href="#">Something else here</a>
  </div>
</div>

dropdown menu bootstrap

<div class="collapse navbar-collapse">
    <ul class="navbar-nav mr-auto">
      	<li class="nav-item">
      		<a class="nav-link" href="#">Clientes</a>
      	</li>
      	<li class="nav-item">
      		<a class="nav-link" href="#">Fornecedores</a>
      	</li>
     	<li class="nav-item dropdown">
          <a  class="nav-link dropdown-toggle" href="#" data-toggle="dropdown">
            Veículos
          </a>
          <div class="dropdown-menu">
            <a class="dropdown-item" href="#">Carros</a>
            <a class="dropdown-item" href="#">Marcas</a>
            <a class="dropdown-item" href="#">Modelos</a>
          </div>
    	</li>
	</ul>
</div>