What is the effect of the Lower function on a string?

The Lower function is specifically designed to convert all characters in a string to their lowercase equivalents. When applied to a string, it ensures that regardless of the original case of each character, the output will display them uniformly in lowercase. This functionality is particularly useful in data processing and analysis, where consistency in text data can improve comparison operations, sorting, and grouping.

In contrast, other functions mentioned in the options perform different tasks: one capitalizes words, another repeats strings, and a different one extracts substrings. Each of these has distinct applications but does not pertain to altering the case of the letters within a string. Hence, recognizing that the Lower function's primary role is to change all characters in a string to lowercase solidifies the understanding of its purpose and application in Qlik Sense and similar data environments.