What is a dynamic link library and how does it work?

Answer 1

dynamic Link library ( dll ) are modules where we store data and function.

in dll there are two types of functions.
exported , internal

exported can be used from the main application.

dll is used by application .exe files

Answer 2

A dll is a binary module that sits on the computer as a separate file from the exe program.
It can be shared, ie can be used by different executable programs, so this reduced the overall disk space usage.

https://stackoverflow.com/questions/124549/what-exactly-are-dll-files-and-how-do-they-work