I´ve just installed STM32Cube and I´m looking for C complier documentation including available functions library. I´m new in this IDE and I inteded to develop an application for STM32F030CC. Thanks for your atention.

[TDK]

The best documentation is from the source files themselves. When you create a project, these files become a part of it and you can view them as needed.

STM32CubeMX/STM32CubeIDE can generate initialization code to get you familiar with how to use things.

There is also this manual, but I think the source files are a better place to find information.

https://www.st.com/resource/en/user_manual/dm00122015-description-of-stm32f0-hal-and-lowlayer-drivers-stmicroelectronics.pdf