What is a microcontroller, software, Pic microcontrollers, programming

Microcontroller manufacturers and programmable 8 bit microcontrollers. Wireless, usb, lcd, pic, embedded and low power 8 bit microcontrollers. what is an 8 bit microcontroller and its programming software. 

https://www.futureelectronics.com/p/semiconductors--microcontrollers--8-bit/pic16f877a-i-l-microchip-7448236