The service disconnect and rapid shutdown system are two of the most inspected elements of a residential solar install. The PV system DC disconnect is required by 690.15 - it must be accessible, lockable, and capable of disconnecting all ungrounded conductors.
Rapid shutdown: per 690.12 (2020 and 2023 NEC), all PV conductors on or inside a building must be reduced to under 30V within 30 seconds of initiating rapid shutdown. The initiating device is typically a labeled switch at the service entrance so firefighters can find it. Enphase systems use an IQ System Controller that initiates rapid shutdown via the same powerline communication it uses to monitor inverters. SolarEdge systems use the SetApp interface and a rapid shutdown transmitter at the inverter.
Labeling requirements are extensive and specific for solar - 690.54 and 690.56 specify what labels go where. The service entrance needs an irradiance warning label. The solar rapid shutdown switch needs a specific label. Anywhere the solar wiring is accessible, you need hazard labels. Print the correct labels before your install day - inspectors will fail you for missing or incorrect labels even when the wiring is perfect.