How does the front-end data update the front-end data through the WordPress backend? Can anyone help explain it?

Question

How is the front-end data? Update the front-end text and image content through the WordPress back-end template.

PHP can include HTML code. I can understand a little bit, but in HTML, PHP code cannot be written. Generally, websites use PHP and HTML mixed-written PHP files, or pictures should be written separately. ? ?

Answer 1

The picture is too bad. Can't see clearly. I don’t want to see either