Use the navigator.clipboard API to copy any text with a single click. It requires HTTPS.

HTML

<button class="lotgrafix-copy" data-copy="Text to copy">Copy</button>

main.js

document.addEventListener( 'click', function ( e ) {
    var btn = e.target.closest( '.lotgrafix-copy' );
    if ( ! btn ) {
        return;
    }
    navigator.clipboard.writeText( btn.dataset.copy ).then( function () {
        btn.textContent = 'Copied!';
        setTimeout( function () {
            btn.textContent = 'Copy';
        }, 2000 );
    } );
} );