inline form elements

HTML

<script src="//code.jquery.com/jquery-3.3.1.slim.min.js"></script>
<link rel="stylesheet" href="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script>
<script src="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<form class="form-horizontal" name="FORMNAME" method="post" action="ACTION" enctype="multipart/form-data">
    <div class="form-group">
        <label class="control-label col-sm-2" for="naam">Naam:&nbsp;*</label>
        <div class="col-sm-10">
            <input type="text" require class="form-control" id="naam" name="Naam" placeholder="Uw naam" value="{--NAAM--}" >
            <div id="naamx" class="form-error form-hidden">Wat is uw naam?</div>
        </div>
    </div>

    <div class="form-row">

        <div class="form-group col-5">
            <label class="control-label col-sm-4" for="telefoon">Telefoon:&nbsp;*</label>
            <div class="col-sm-12">
                <input type="tel" require class="form-control" id="telefoon" name="Telefoon" placeholder="Telefoon nummer" value="{--TELEFOON--}" >
                <div id="telefoonx" class="form-error form-hidden">Wat is uw telefoonnummer?</div>
            </div>
        </div>

        <div class="form-group col-5">
            <label class="control-label col-sm-4" for="email">E-mail: </label>
            <div class="col-sm-12">
                <input type="email" require class="form-control" id="email" name="E-mail" placeholder="E-mail adres" value="{--E-MAIL--}" >
                <div id="emailx" class="form-error form-hidden">Wat is uw e-mail adres?</div>
                    </div>
                </div>

        </div>

    <div class="form-group">
        <label class="control-label col-sm-2" for="titel">Titel:&nbsp;*</label>
        <div...