JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <textarea name="" id="txt" cols="30" rows="10"></textarea>
    <button>Submit</button>
</div>

CSS

div{
    display:inline-block;
    position:relative;
}

button{
 position:absolute;
 bottom:10px;
 right:10px;
}