introduction.md

A str typed object in Python is an immutable sequence of Unicode code points. This could include letters, numbers, punctuation, etc. To manipulate strings, Python provides string methods that can transform a string into other types, create new strings based on method arguments, or return information about the string. Strings can be concatenated with +.

Immutability means that a string's value doesn't change; methods that appear to modify a string actually return a new instance of str.