JSFiddle - React, Tailwind, and code Playground

HTML

<div class="a">header
    <div class="szukajka">lupa</div>
</div>

CSS

.a {
    height: 100px;
    width:100%;
    background-color:#444;
}
.szukajka {
    /* tu najwazniejsze */
    float:right;
    position:relative;
    right:100px;
    /* ========== */
    width:50px;
    height:20px;
    background-color:red;
}