My web server version is Apache/2.4.41 running under Ubuntu 19.10 , so first off, let’s install what’s Apache needs, the MPM (Multi-Processing Module) :
apt-get install libapache2-mpm-itk
That’s it, assuming you had a working Apache setup to start with. Then in the configuration files files for each of your sites put
The If IfModule is just to ensure that the MPM is running and the first www-data is the user to run the website (for details on how to create a user see this) and the second the group so, of course, change it o the user you really want to run the site & then restart Apache.
And that’s it. You should be able to test it but putting a small script into site & running it from your browser, say a file called “info.php”:
When it runs you should see the user name you set in the configuration file