Which function can capitalizes the first letters of each word in a string?

The function that capitalizes the first letters of each word in a string is indeed the Capitalize function. This function is specifically designed to manipulate text by transforming the first character of each word to uppercase, enhancing readability and presentation of textual data.

In contrast, the other functions serve different purposes. For instance, the Upper function converts all letters in a string to uppercase, but it does not selectively capitalize the first letter of each word. The Mid function is primarily used for extracting a substring from a string based on defined positional parameters, while the Qualify function is used to qualify field names in Qlik Sense, helping to avoid naming conflicts. Understanding the specific use of character manipulation functions is crucial for effective data transformation and presentation in Qlik Sense applications.