Where is nginx default config file on Ubuntu 18.04

Hi,
I've followed this tutorial https://www.howtoforge.com/tutorial...g-3/2/#-install-nginx-php-phpfpm-and-fcgiwrap and most things work fine...
Except I struggle every time I would like to change something globally on nginx, because I simply cannot find its default global config file.
And NO, it looks like it is not /etc/nginx/nginx.conf (...because, for example, I can add some headers there, but they are simply not created for website)

 

Anybody? Till?

 

Hmmm...but why those headers and options, which I setup there, do not kick-in for websites automagically?
For example, I have some x-headers setup there, and for WordPress optimized links. like this:

Code:

location / {
  try_files $uri $uri/ /index.php?$args;
}

But no, websites do not obey those settings.
Any idea why?