Change
<div
  id="loc-name"
></div>
<div
  id="loc-phone-number"
></div>

<script>
  window.onload = function() {
    // Retrieve the value from sessionStorage
    var locationNumber = sessionStorage.getItem('location_phone_number');

    // Check if the value is not null
    if (locationNumber) {
      // Set the inner HTML of the div to a clickable link with tel href
      document.getElementById('loc-phone-number').innerHTML = '<a href="tel:' + locationNumber + '">' + locationNumber + '</a>';
    }
  };
</script>

With a Project Manager overseeing every step, we move quickly on all repairs, typically completing work within 3-5 days, and roof maintenance program members receive priority scheduling.