Simple Return to Top,

return-to-top.css

/* Return To Top */
#return-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: rgb(0, 0, 0);
    background: rgba(0, 0, 0, 0.7);
    width: 50px;
    height: 50px;
    display: block;
    text-decoration: none;
    -webkit-border-radius: 35px;
    -moz-border-radius: 35px;
    border-radius: 35px;
    display: none;
    -webkit-transition: all 0.3s linear;
    -moz-transition: all 0.3s ease;
    -ms-transition: all 0.3s ease;
    -o-transition: all 0.3s ease;
    transition: all 0.3s ease;
}

#return-to-top i {
    color: #fff;
    margin: 0;
    position: relative;
    left: 16px;
    top: 13px;
    font-size: 19px;
    -webkit-transition: all 0.3s ease;
    -moz-transition: all 0.3s ease;
    -ms-transition: all 0.3s ease;
    -o-transition: all 0.3s ease;
    transition: all 0.3s ease;
}

#return-to-top:hover {
    background: rgba(0, 0, 0, 0.9);
}

#return-to-top:hover i {
    color: #fff;
    top: 5px;
}

return-to-top.html

	<!-- RETURN TO TOP -->
	<a href="javascript:" id="return-to-top"><i class="fa fa-angle-up" aria-hidden="true"></i></a>
	<!-- RETURN TO TOP -->

return-to-top.js

/*===== Scroll to Top ==== */
jQuery(window).scroll(function() {
	if (jQuery(this).scrollTop() >= 50) {
		jQuery('#return-to-top').fadeIn(200);
	} else {
		jQuery('#return-to-top').fadeOut(200);
	}
});
jQuery('#return-to-top').click(function() {
	jQuery('body,html').animate({
		scrollTop : 0
	}, 500);
});