<article class="service-box col-12">
    <div class="image">
    <i href="#" class="fa fa-arrows"></i>
    </div>
    <div class="inner">
    <header>
    <h3>Fully Responsive</h3>
        </header>
        <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer nec enim eros. Nam vestibulum eros a tempor posuere. Phasellus at rhoncus nulla, sed imperdiet eros. Suspendisse pellentesque dui gravida nisi mollis, fermentum sagittis ligula elementum. Nulla facilisi. Maecenas rutrum commodo ipsum, id lacinia massa. Nullam at laoreet tortor. Maecenas lacinia sed metus et lobortis.</p>
    </div>
    </article>

Replace the whole <i> tag with the <img> tag.

<article class="service-box col-12">
    <div class="image">
    <img src="https://your direct link or correct image path">
    </div>
    <div class="inner">
    <header>
    <h3>Fully Responsive</h3>
        </header>
        <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer nec enim eros. Nam vestibulum eros a tempor posuere. Phasellus at rhoncus nulla, sed imperdiet eros. Suspendisse pellentesque dui gravida nisi mollis, fermentum sagittis ligula elementum. Nulla facilisi. Maecenas rutrum commodo ipsum, id lacinia massa. Nullam at laoreet tortor. Maecenas lacinia sed metus et lobortis.</p>
    </div>
    </article>