What are the best online tools or apps for changing fonts, and how do "font changers" work to modify text styles?

This question seeks information about tools or apps that allow users to change the appearance of text by using different font styles. It also explores the underlying mechanism of "font changers," focusing on how they modify text to display in various styles, such as bold, italic, cursive, or decorative formats. The goal is to identify practical resources for font customization while understanding their functionality. www.fontschanger.com