A function is BEST used for enabling programs to:

 A function is best used for enabling programs to define variables to hold different values. A function is a named block of code that performs a specific task or operation. A function can have one or more parameters, which are variables that hold the input values for the function. A function can also have a return value, which is the output value that the function produces. A function can be called or invoked by other parts of the program to execute the code inside the function. A function can help programs to avoid repeating the same code, improve readability and modularity, and reduce errors and complexity. References : The Official CompTIA IT Fundamentals (ITF+) Study Guide (FC0-U61), page 133.