You have to customize the theme's file in top-bar go to wp-content >> themes >> education >> template-parts >> header >> top-bar >> selective-icons.php
and Find
case "wc_socialoptions_phone":
echo '<li><i class="fa fa-phone"></i> '.esc_html(get_theme_mod('wc_socialoptions_phone', $default_phone)).'</li>';
break;
If you want to link both icon and the phone number then add a <a href= after <li> otherwise add after </i> and closing tag for </a > enter before </li> in both cases like below.
case "wc_socialoptions_phone":
echo '<li><a href="tel:+1231231234"><i class="fa fa-phone"></i> '.esc_html(get_theme_mod('wc_socialoptions_phone', $default_phone)).'</a></li>';
break;
That will open the phone number like in Skype for desktop if your browser allow, and in phone dialpad for mobile phones. Make sure you change +1231231234 with your phone number thanks.