You have to make a file in /etc/systemd/system/ with .service format.
format of content into this :
[Unit]
Description={{description of your service}}
After=network.target
[Service]
User=root
Group=www-data
WorkingDirectory={{directory of your service}}
ExecStart={{the needed command to start }}
[Install]
WantedBy=multi-user.targetYou can also configure many things according to your needs.