Functional testing is to test the functionality of the software application under test. Basically, it is to check the basic functionality mentioned in the functional specification document. Also, check whether the software application is meeting the user expectations. We can also say that checking the behavior of the software application against test specification.
During functionality testing, we check the core application functions, text input, menu functions and installation, and setup on localized machines, etc.
What all need to be check in Functional Testing
Is software is functioning as it should do?
Is software is not functioning as it should not do?
Is software is not doing as it is not intended to do?
Are Core application functions working fine?