why do we use functions in python code example

Example 1: python functions

def myFunction(say): #you can add variables to the function
  print(say)

myFunction("Hello")

age = input("How old are you?")

myFunction("You are {} years old!".format(age))

#this is what you get:

Hello
How old are you?
>>11 #lol my real age actually
You are 11 years old!

Example 2: how to define functions in python

def add(number):
  equation = 5 + number
  print(equation)
  
 
add(10)

output:
  
  15