What is the use of Actions and Functions in QTP? What do you know about Actions, functions in QTP?

Actions are specific to QTP. Normally a single or combination of multiple actions make a QTP script. Actions can associate with OR (object repository).

Functions are a piece of VB script code that has a variables and after execution will produce a return value that will be passed to the script back for further usage. Functionas can not associate with OR.

When we need to add some functionality to qtp script then we go for functions and call them in scripts.