setTimeout(() => {
  var a = document.createElement('div');
  a.innerHTML = `<a href="https://api.whatsapp.com/send?phone=34667234802&text=Hola,%20me%20gustar%C3%ADa%20recibir%20m%C3%A1s%20informaci%C3%B3n%20acerca%20de%20Utel%20universidad" target="_blank" class="whatsapp"><img style="border-radius: 50px" src="https://cmsutel.s3.amazonaws.com/3536445_0552d85261.png" alt="WhatsApp"></a>`;
  document.body.appendChild(a);

  var s = document.createElement('style');
  s.textContent = `
    .whatsapp {
      position: fixed;
      width: 60px;
      height: 60px;
      bottom: 15%;
      right: 40px;
      border-radius: 50px;
      z-index: 10;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    @media screen and (max-width: 768px) {
      .whatsapp {
        display: none;
      }
    }
  `;
  document.body.appendChild(s);
}, 1500);

(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-MFB49HZ');

const styleElement = document.createElement('style');
    styleElement.innerHTML = `
        .css-1i8v9ym{
            width: 30px;
            height: 30px;
        }
    `;

    document.head.appendChild(styleElement);

¿Todavía tienes dudas?