JSFiddle - React, Tailwind, and code Playground

HTML

<select id="selectVendor">
 <option value="55" selected="selected">Company A</option>
 <option value="56">Company B</option>
 <option value="57">Company XYZCYK</option>
</select>

<input type="text" id="txtCompany" value="empty" />

JavaScript

$(document).ready(function(){
   $("#txtCompany").val(
       $("#selectVendor option").eq(
         Math.floor(Math.random()*$("#selectVendor option").length)
         ).val()); 
});