<style type="text/css">
    div.floating-bottom{
        position:fixed;
        bottom:0;
        width:100%;
        height:50px;
        background:#333333;
        text-align:center;
        font-size:18px;
        color:white;
        padding:3px 0;
        z-index: 999999;
    }
</style>

<div class="floating-bottom">
    Order / Konsultasi:
    <a href="https://api.whatsapp.com/send?phone=6285728434446&text=Order/Konsultasi">
        <button class="btn btn-primary small">
            <i class="fa fa-whatsapp"></i> 6285728434446
        </button>
    </a>
    <a href="tel:6285728434446">
        <button class="btn btn-primary small">
            <i class="fa fa-phone"></i> 6285728434446
        </button>
    </a>
</div>