Embedding iframes into web pages is a common practice when you need to include content from another source, such as video players or interactive maps. However, ensuring that your iframe is responsive and adapts well to various devices and screen widths requires the right code. Here's a simple code for a responsive iframe:

<div style="position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden;">
    <iframe src="https://www.example.com" style="position: absolute; top: 0; left: 0; width: 100%; height: 100%; border: 0;" allowfullscreen></iframe>
</div>

How does this code work?

• The <div> container holds the iframe and sets the aspect ratio for responsiveness.
• padding-bottom: 56.25%; sets the aspect ratio (16:9), allowing the iframe to adjust to the container's width.
• position: relative; maintains the relative position of the container, which is important for the iframe's position.
• position: absolute; allows the iframe to fill the entire space within the container.
• top: 0; left: 0; aligns the iframe to the top-left corner of the container.
• width: 100%; height: 100%; ensures the iframe occupies all available space inside the container.
• border: 0; removes borders from the iframe.
• allowfullscreen enables fullscreen mode for the embedded content if supported.

This code ensures that your iframe is responsive and nicely adjusts to various screen sizes, which is essential for a user-friendly and consistent web page.