Why don't php and html work together?

Question

Apache HTTP Server

In php and html don't work together, linux mint - apache2. And they work separately. if you insert php code, then in this case it gives an error 500. Where can I see the log and how to make this miracle of technology work together ?.

Answer 1

/etc/apache2/sites-enabled/site.com.conf - add after
ErrorLog /home/www/site.com/error.log
and there will be site logs

Answer 2

However, everything works except for syntax highlighting in gedit, but it starts working if the script is inserted into the tag <script>, except that the script itself is not executed (((. In a riddle. And by the way, the log cannot be displayed separately? what could be the reason?