See https://www.devdungeon.com/content/one-line-http-servers.

Debian instructions:

apt install apache2 php libapache2-mod-php php-pdo-sqlite
 
# Enable/disable modules (/etc/apache2/mods-avaialable/)
a2enmod userdir
a2dismod userdir
 
# Enable/disable sites (/etc/apache2/sites-available/)
a2ensite mysite
a2dissite mysite

The user is www-data and the default webroot is /var/www/html/ (Debian).

See https://www.devdungeon.com/content/nginx-tutorial.

apt install nginx

To add PHP, use PHP FPM

apt install php-fpm

Then in your vhost file, include the following snippet:

  # In your nginx vhost server entry:
  index index.php;
  # Have all .php files pass through php-fpm
  location ~ \.php$ {
    include snippets/fastcgi-php.conf;
    # Find the right socket in /run/php/
    fastcgi_pass unix:/run/php/php7.3-fpm.sock;
  }