This is the 3763rd most frequent Japanese word.
つづる
"To spell" or "to compose."
Here, 'つづる' is used in the sense of '[to compose/issue/write],' referring to the act of writing or composing text in a thoughtful manner.
手紙をつづるのは私の趣味です。
Composing letters is my hobby.
In this example, 'つづる' means '[to describe/compose],' indicating the action of putting one's story into written form.
彼は自分のストーリーを本につづった。
He spelled out his story in a book.
Here, 'つづる' signifies '[to spell],' asking someone to spell out their name in alphabetical characters.