This refers to Jesus. Translate as "the Word" if possible. If "Word" is feminine in your language, it could be translated as "the one who is called the Word." See how you translated this in [John 1:1](./01.md).
Here "flesh" represents "a person" or "a human being." Alternate translation: "became human" or "became a human being" (See: [[rc://en/ta/man/translate/figs-synecdoche]])