The page code usually means a set of elements in the markup language HTML, which serve to format it and display it in a form of a user-friendly way. 

Most often, the name option is used - HTML code.

You can view the code of any web page directly in browser

The easiest way is to use the key combination “Ctrl + U”. 

As a result, the window that opens will display numbered lines containing various parameters and commands on the Latin alphabet, enclosed in < > (tags) brackets. Interference with them will be parts of the text, which before that could be seen on the page. 

This is all together and there is a page code. It is in this form that browsers perceive it and, taking into account the commands indicated in it, adapt the pages for visual display. 

Search engines when indexing pages also analyze the source code that is hidden from the eyes of an ordinary user.