Titles, boldface, and subheadings are three examples of

I would say they are examples of format for a written work like an article or a book . Boldface highlights certain parts of the text ie makes them stand out and titles separate the topics or could be the chapters and subheadings break the headings or titles down into smaller sections that constitute the whole say chapter.

The girl walked up to the dog. of course she was only three years of age so she had no knowledge of what she was doing. she walked up to the wild beast, without considering the consequences. but she would find out soon. she held out her hand to touch the mangled canine. snap. the toddlers hand was soon covered in a red liquid.