<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script>
    jQuery(document).ready(function (jQuery) {
    jQuery("#field_IX05").html('<option value="field_IX05_V0">FedEx Plugin</option>'+
      '<option value="field_IX05_V1">USPS Plugin</option>'+
      '<option value="field_IX05_V2">DHL Plugin</option>');
jQuery("#field_VU59").change(function(){  //field_VU59 is the input field ID of first drop-down
 jQuery("#field_IX05").html('');  //field_IX05 is the input field ID of second drop-down
 if(jQuery("#field_VU59").val()=="field_VU59_V0")
 {
     var html = '<option value="field_IX05_V0">FedEx Plugin</option>'+
                '<option value="field_IX05_V1">USPS Plugin</option>'+
                '<option value="field_IX05_V2">DHL Plugin</option>';
       jQuery("#field_IX05").append(html);
 }
 else if(jQuery("#field_VU59").val()=="field_VU59_V1")
 {
     var html = '<option value="field_IX05_V3">6 months</option>'+
                '<option value="field_IX05_V4">12 months</option>'+
                '<option value="field_IX05_V5">24 months</option>';
      jQuery("#field_IX05").append(html);
 }
 else if(jQuery("#field_VU59").val()=="field_VU59_V2")
 {
    var html = '<option value="field_IX05_V6">Single Site License</option>'+
               '<option value="field_IX05_V7">Five Site License</option>'+
               '<option value="field_IX05_V8">Ten Site License</option>';
      jQuery("#field_IX05").append(html);
 }
 });
});
</script>