By itself, your example sentence:
- 🚫 How this word is written?
is not standard English.
If this is a question, it should use inversion:
- ✔️ How is this word written?
If this is a phrase, it depends on the context:
The two police officers looked at a word written on the sidewalk (graffiti).
The teacher pointed to the blackboard, which says "times".
- ✔️ Carol: How this word is written depends on its usage. If it refers to a newspaper, it should be capitalized, like "The Times". If it refers to arithmetic, it should be lower-case, like "five times three".