WordPress Social Sharing Links

functions-1.php

/**
 *  Return Social Sharing Links.
 */
function theme_slug_social_sharing() {

	// Get current page URL.
	$page_url = get_permalink();

	// Get current page title.
	$page_title = get_the_title();

	// Create Array with Social Sharing links.
	$links = array(
		'facebook' => array(
			'url'  => 'https://www.facebook.com/sharer/sharer.php?u=' . $page_url . '&t=' . $page_title,
			'text' => 'Facebook',
		),
		'twitter' => array(
			'url'  => 'https://twitter.com/intent/tweet?text=' . $page_title . '&url=' .$page_url,
			'text' => 'Twitter',
		),
		'googleplus' => array(
			'url'  => 'https://plus.google.com/share?url=' . $page_url . '&t=' .$page_title,
			'text' => 'Google+',
		)
	);

	// Create HTML list with Social Sharing links.
	$html = '<ul class="social-sharing-links">';

	foreach( $links as $key => $link ) {

		$html .= sprintf( '<li><a href="%1$s" target="_blank">%2$s</a></li>',
			esc_url( $link['url'] ),
			esc_html( $link['text'] )
		);
	}

	$html .= '</ul>';

	return $html;
}

functions-2.php

/**
 * Add the social sharing buttons to post content
 *
 * @return string
 */
function theme_slug_add_social_sharing_to_content( $content ) {

	// Only display sharing links in single post and pages.
	if ( ! ( is_singular() && is_main_query() ) ) {
		return $content;
	}

	return $content . theme_slug_social_sharing();
}
add_filter( 'the_content', 'theme_slug_add_social_sharing_to_content' );

style.css

ul.social-sharing-links {
	display: flex;
	padding: 0;
	list-style: none;
}

ul.social-sharing-links li a {
	display: block;
	margin-right: 0.5em;
	padding: 0.25em 1em;
	border-radius: 5px;
	color: #fff;
}

ul.social-sharing-links li a[href*="facebook.com"] {
    background: #3b5998;
}

ul.social-sharing-links li a[href*="twitter.com"] {
    background: #55acee;
}

ul.social-sharing-links li a[href*="plus.google.com"] {
    background: #dc4e41;
}