JSFiddle - React, Tailwind, and code Playground

HTML

<aside class="quickcontactform">
    <div class="quickcontactformheader">
        <h2>Need help evicting a tenant?</h2>
        <h3>Don't Delay</h3>
        <p>Please complete the form below</p>   
    </div>
    <p>'ere is more content sire</p>
    <p>a be a pleased with it I am</p>
    </aside>

CSS

.quickcontactform {
    width:350px;
    float:right;
    background:#fff;border-radius:10px;
    overflow:hidden;    
}
.quickcontactformheader {
    background:#f0cf35; 
    position:relative;
}

.quickcontactformheader:after {
content:'';
    position:absolute;
    top:100%;
     width: 0; 
     height: 0; 
     border-left: 175px solid transparent; 
     border-right: 175px solid transparent; 
     border-top: 30px solid #f0cf35;
}