text-transform: uppercase;

This CSS property is used to transform all the text in an element to uppercase. It is particularly useful when you want to make text more visible or emphasize it. When applied, it will change all lowercase letters to uppercase, while leaving uppercase letters and other characters unchanged. Here is an example:

p {
  text-transform: uppercase;
}

This will make all text in the `p` element uppercase. You can also use this property with other CSS properties like `font-size` and `color` to further customize the appearance of the text in your element.