To add a website to your blog using an iframe, follow these steps:

 For Blogger:
1. Login to Blogger: Go to [Blogger.com](https://www.blogger.com) and log in to your account.
2. Go to the post or page: Open the post or page where you want to embed the website.
3. Switch to HTML view: In the post editor, switch to the HTML mode by clicking the "HTML" button.
4. Insert iframe code: Add the following code where you want the website to appear:
   ```html
   <iframe src="https://www.example.com" width="800" height="600" frameborder="0" allowfullscreen></iframe>
   ```
   - Replace `"https://www.example.com"` with the URL of the website you want to embed.
   - Adjust the `width` and `height` as needed.
   - You can also set `frameborder="0"` to hide the frame border and `allowfullscreen` if you want the option to make it fullscreen.

5. Preview and Publish: Click on "Preview" to see how it looks, then publish your post or page.

 For WordPress:
1. Login to WordPress: Go to your WordPress dashboard.
2. Edit the post or page: Open the post or page editor where you want to add the iframe.
3. Add iframe in HTML view: In the block editor, switch to "Code editor" or add a "Custom HTML" block.
4. Insert iframe code: Use the same iframe code as mentioned above:
   ```html
   <iframe src="https://www.example.com" width="800" height="600" frameborder="0" allowfullscreen></iframe>
   ```

5. Save and Publish: Preview and publish your changes.

 Notes:
- Some websites block embedding using iframes due to security policies (like using the `X-Frame-Options` header). If you encounter a problem with embedding, the website might not allow iframe embedding.
- Always ensure the website you are embedding allows you to do so to avoid copyright or policy violations.