Other updates can be bundled in the monthly updates, but can also appear separately. Apps are updated in Play Store.
It runs automatically if the phone is set up with a Google account, with default settings, with mobile data and WiFi access.
The system update check and app updates run when the phone is connected to a charger and mobile data or WiFi. It can also be checked manually in Play Store > My apps & games, and in Settings > System > System updates.