Search box with icon in Navbar in bootstrap 4

Here is the code snippet that display the search box with icon at the top-right side of the navbar.

When navbar is collapsed in the small screen, search box goes inside the navbar.

<nav class="navbar navbar-expand-sm navbar-toggleable-sm navbar-light bg-white border-bottom box-shadow mb-3">
            <div class="container">
                <a class="navbar-brand" asp-area="" asp-controller="Home" asp-action="Index">BrandName</a>
                <button class="navbar-toggler" type="button" data-toggle="collapse" data-target=".navbar-collapse" aria-controls="navbarSupportedContent"
                        aria-expanded="false" aria-label="Toggle navigation">
                    <span class="navbar-toggler-icon"></span>
                </button>
                <div class="navbar-collapse collapse">
                    <ul class="navbar-nav flex-grow-1">
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Index">Home</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Tutorials">Tutorials</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Privacy">Privacy</a>
                        </li>
                    </ul>

                    <form action="/People/Search" method="Post" class="form-inline my-2 my-lg-0">
                        <div class="input-group">
                            <input type="text" name="keyword" class="form-control" placeholder="Keyword to seach">
                            <div class="input-group-append">
                                <button class="btn btn-secondary" type="button">
                                    <i class="fa fa-search">Go</i>
                                </button>
                            </div>
                        </div>
                    </form>      
               
                </div>
            </div>
        </nav>