String replacement is a programming technique used to substitute specific sequences of characters within a string with new characters. This is commonly used in various programming languages, such as Python, Java, and JavaScript, to modify text data. For example, if you have the string "Hello, World!" and want to replace "World" with "Everyone," the result would be "Hello, Everyone!" The process typically involves using built-in functions or methods that search for a target substring and replace it with a specified replacement substring. This can be useful for tasks like correcting typos, formatting text, or updating information in a dataset.