JSFiddle - React, Tailwind, and code Playground

HTML

<div class="new-field-popup"></div>

CSS

.new-field-popup{
    position: absolute;
    width: 200px;
    height: 57px;
    padding: 20px;
    border-radius: 5px;
    top: 10px;
    left: 10px;
    border: 1px dashed rgb(177, 177, 177);
}

.new-field-popup:after{
    content: '';
    border-bottom: 1px dashed rgb(177, 177, 177);
     border-right: 1px dashed rgb(177, 177, 177);
     background-color:white;
    position: absolute;
    left: 110px;
    bottom: -10px;
    width: 20px;
    height: 20px;
    transform: rotate(45deg);
}