OTA (Over the Air) Programming is a feature of any WiFi-enabled microcontroller like ESP32 and ESP8266 that allows these devices to upgrade their firmware or software wirelessly without any physical access. This feature can be used to reprogram the devices that are fixed on a roof or any other place where connecting cable is difficult. Using OTA, you can send an update to multiple microcontrollers or devices that are on the same network. For example, this feature can be used to send updates for resolving the bugs, adding some features, etc.
[original story: Circuit Digest]