Check apache2 status

systemctl status apache2

Stop apache2 service

sudo systemctl stop apache2

Start apache2 service

sudo systemctl start apache2

Restart apache2 modules and sites

sudo apache2ctl restart

Enable apache2 site

sudo a2ensite <a file located in /etc/apache2/sites-available/>

You should omit the .conf file extensions

Disable apache2 site

sudo a2dissite <a file located in /etc/apache2/sites-enabled/>

You should omit the .conf file extensions

Register another site config

1. Copy any file located in /etc/apache2/sites-available/
2. Change its values to fit your requirements

You may be interested on checking this documentation: https://httpd.apache.org/docs/2.4/vhosts/examples.html