service is less functional wrapper around systemctl command on systemd based distros.
I’m a long time Linux user and got a habit to start/stop things using service command.
I never really thought about what exactly it does. I mean, I know I can start Apache or something else with it and it’s something related to init system of my distro.
Usually when you install Apache or PHP-FPM those things become recognizable by service command and you can call service program start when you want to start a service.