Check out example codes for "redesign html select". It will help you in understanding the concepts better.

Code Example 1

#my_selection {
    -webkit-appearance: none; 
   -moz-appearance: none;
   appearance: none;       /* remove default arrow */
   background-image: url(../img/drop-down.png);  /* add custom arrow */
   background-repeat: no-repeat;
   background-position:right center;
}

Learn ReactJs, React Native from akashmittal.com