For the built-in function, I used the strlen() function. This function counts the amount of characters that are in a string including spaces, punctuation, etc. Then, when the function is called again, it displays how many characters are in that string. Since the phrase I chose to count the string length of had 18 characters, the function stated that the phrase had 18 characters when it was called.
For the user-defined function, I chose to do a simple function that would greet people by their first name with the simlish greeting SulSul, which means hello. How this function works is that I had my function take the argument of $fname, and then inside the function I concatenated the greeting with the function argument in the echo statement in the function. Then, When the function is called, I put actual first names instead of $fname so the function was greeting real people. I called this function multiple times to get the result shown above these explanations.