#Use systemctl command to start the service on boot. For example:
$ sudo systemctl enable apache2
#Alternatively, if you also wish to enable and start the service at the same time you may execute:
$ sudo systemctl enable --now apache2
#Once the service is enabled to start on boot you confirm its status once again by:
$ sudo systemctl status apache2
#To disable service to start on boot use systemctl command again. For example:
$ sudo systemctl disable apache2