JSFiddle - React, Tailwind, and code Playground
HTML
<label for="itemImageId" style="color: gray" id="labelForImageUploadID">Item image</label>
JavaScript
document.getElementById("labelForImageUploadID").style.color = "red";
<label for="itemImageId" style="color: gray" id="labelForImageUploadID">Item image</label>
document.getElementById("labelForImageUploadID").style.color = "red";