JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
    <input class="custom-input" type="text" /> <a class="button"></a>

</div>

CSS

.wrapper{
    width: 300px;
    display: inline-block;
}

.custom-input{
    display: inline-block;
}

.button{
    width: 20px;
    height: 20px;
    background-color: #ccc;
    display: inline-block;
}