Can C# Interact With Other Programs?

Question

I'm considering learning C# in order to develop some custom business solutions, and I just wanted to ask some experts first to get an idea of the language's capabilities. Specifically, there is a third-party program that I use manually for work, basically clicking items within the program in order to generate a report. 

Is it possible to create a C# application that could interact with this 3rd party program and automate all of the manual clicking I have to do? To be clear, I would not be able to modify the 3rd party program in any way. Also, this would be for Windows, and the 3rd party program is NOT Microsoft software.

Is this possible, and if so where would it rank from 1-10 in terms of difficulty.

Thanks!