publicheaderadmin.php

<nav class="navbar navbar-expand-lg navbar-light bg-light">
    <a class="navbar-brand" href="#">Shopping Website</a>
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent"
            aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
    </button>

    <div class="collapse navbar-collapse" id="navbarSupportedContent">
        <ul class="navbar-nav mr-auto">
          <li class="nav-item active">
                <a class="nav-link" href="add_admin.php">Sign Up <span class="sr-only">(current)</span></a>
            </li> <li class="nav-item active">
                <a class="nav-link" href="loginpage.php">Log in <span class="sr-only">(current)</span></a>
            </li>
            <!--            <li class="nav-item active">-->
            <!--                <a class="nav-link" href="admin_changepassword.php">Change Password <span-->
            <!--                            class="sr-only">(current)</span></a>-->
            <!--            </li>-->

        </ul>

    </div>
</nav>