What is string formatting in python 3? Please explain simply

Answer 1

It means displaying values represented by variables of different datatypes in specific formats right there within a string.

For example, displaying fractions with a given digit precision or in a form of a percentage and alike.

Check out the official docs about it:
https://docs.python.org/3.5/library/string.html#format-string-syntax

Since 3.6, there is a new way of doing this - formatted string literals:
https://docs.python.org/3/reference/lexical_analysis.html#f-strings

Answer 2

a = 3
b = 2

print(f"{a*b} {a+b} {3-1}") # 6 5 2

One way you can format, called "f-strings"