To apply an iron-on embroidered patch, first, place the patch on your desired fabric surface. Cover the patch with a thin cloth to protect it from direct heat. Set your iron to a medium-high setting, without steam, and press it firmly over the cloth for 20-30 seconds. Let it cool for a few minutes, ensuring the patch adheres properly. For sew-on patches, position the patch and secure it with pins or fabric glue. Use a sewing machine or hand stitch around the edges of the patch for a more durable hold.