Asio was originally introduced by Steinberg. The main reason they introduced it was to improve latency. Using windows drivers there was/is a delay between hitting a key on a MIDI piano and the sound being heard. Very old sound cards and even more modern ones not built for music also increase this latency. The other thing ASIO does is ,make it possible to increase the definition of the Audio signal from the Audio engine of our application.
ASIO is now an industry standard and virtually all pro sound cards come with their own ASIO driver written for the card. There is also ASIO4ALL written as a generic driver - dont use this one unless you have to.
The asio Sound card driver typically gives you more control over your levels. The driver is alos the place where you can adjust tyour buffer size. Buffer size is important. The buffer is a kind of temporary holding bay for the sound. A small buffer size reduces latency but can make your application splutter and wheeze. A high buffer size increases latency.
A useable latency value is something under 6 millisecs preferably 4. Anything over siz msecs makes the keyboard feel drudgy. Windows (non Asio) sometimes delivers latency much slow than this.
Typically yuo wont need to know much more than this. Bit if you do:
http://en.wikipedia.org/wiki/Audio_Stream_Input/Output

A good Audio engine deserves ASIO drivers. OF course the driver has to be 32 bit for WIn 32 and 64 for Win64

Win 11 64, Asus Rog Strix z390 mobo, 64 gig RAM, 8700k