JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box">
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse placerat pellentesque placerat. 
    <div class="triangle"></div>
</div>

CSS

body {
    background-color: #eee;
    padding:20px;
}

.box {
    background:white;
    width:200px;
    height:100px;
    box-shadow:0px 0px 15px rgba(0,0,0,0.4);
    position:relative;
    padding:25px;
}

.triangle {
    position: absolute;
    height: 20px;
    width: 20px;
    top: 50%;
    left: 100%;
    transform: translate(-50%, -50%) rotate(-45deg);
    background: white;
    box-shadow:0px 0px 15px rgba(0,0,0,0.4);
}

.box:after {
    position:absolute;
    content: '';
    background: white;
    height:40px;
    width:25px;
    right:0;
    top:50%;
    margin-top:-20px;
}