Untitled

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Pasek TVP</title>
</head>
<body>
  <img id="template" src="template.jpg" width="800" height="426" style="display: none;">
  <input type="text" id="caption" value="" placeholder="Tekst">
  <button onclick="generateImage()">Generuj</button><br>
  <canvas id="canvas" width="800" height="426"></canvas>

  <script>
    function generateImage() {
      const c = document.getElementById("canvas");
      const ctx = c.getContext("2d");

      const img = document.getElementById("template");
      ctx.drawImage(img,0, 0);
      ctx.font = "26px Arial";
      ctx.fillStyle="#fff";
      const caption = document.getElementById("caption").value.toUpperCase();
      ctx.fillText(caption, 165, 382);
    }
  </script>
</body>
</html>