I will share a code to prevent your wordpress posts from copying. Actual it will not stop copying, but it will show a custom message while pasted.
<script type="text/javascript">
function addLink() {
var pageLink = "<BR/><BR/>Read more: " + document.location.href; // Get the current page link
var copytext = "Copying Not Allowed" + pageLink + "<BR/><BR/>Join our Whatsapp group: https://chat.whatsapp.com/GroupName";
var newdiv = document.createElement('div');
// Hide the newly created container
newdiv.style.position = 'absolute';
newdiv.style.left = '-99999px';
// Insert the container, fill it with the fixed text, and define the new selection
newdiv.innerHTML = copytext;
newdiv.style.fontWeight = 'bold';
document.body.appendChild(newdiv);
window.getSelection().selectAllChildren(newdiv);
window.setTimeout(function () {
document.body.removeChild(newdiv);
}, 100);
}
document.addEventListener('copy', addLink);
</script>