The placeholder should show Enter a name* with a white text but the * red. I'm using Bootstrap 4 in Chrome. My HTML and CSS code are these:
.form-control::-webkit-input-placeholder::after {
    color: red;
    text-align: right;
    font-size: 50px;
    content: "*";
}
<input type="text" placeholder="Your Name" class="form-control py-4" style="background: #273a71; color: white; border: 0;">