What is a person's name written by that person called?

The term for a person's name written by that person is known as a signature. A signature serves as a form of personal identification, showing that the individual has willingly signed a document or confirmed their identity. It usually reflects a unique style, which can vary widely from one individual to another.

In contrast, an autograph generally refers to a person's signature specifically in instances like celebrities signing for fans, often as a collectible. Personal marks are not widely defined and can refer to any mark an individual makes, not necessarily their name. Initials represent the first letters of a person's name rather than the full name as presented in a signature. Therefore, the correct choice emphasizes the importance of personal identification through the formal way an individual signs their name.