Just code templates for IoT devices for a demo
Microcomputers are full computers that run an OS (generally Linux). The difference with normal computers is that they generally have input and output pins (GPIO, or General purpose input-output, ports). These input pins allow them to read data from real-world devices and the output pins allow them to act on real-world devices. They also have far fewer resources than normal computers.
See here
Microcontrollers are single-threaded. They just do one thing: run the code given to them. There is generally no OS. They have much, much less resources.
The Pico is an open-source board developped by Raspberry Pi. It has a dual-core ARM processor with 264 kB internal RAM, and 2MB of onboard flash memory. The 'W' version has a wireless chip that supports the 2.4GHz. At the time of writing, it costs less than 10$. All specs here.
Contrary to most microcontrollers that support only C/C++ development, the Pico also supports Python development. See here