what does f in front of string mean python code example

Example 1: python fstring

#python3.6 is required
age = 12
name = "Simon"
print(f"Hi! My name is {name} and I am {age} years old")

Example 2: format specificer f strings python

#!/usr/bin/env python3

val = 12.3

print(f'{val:.2f}')
print(f'{val:.5f}')