I know where he lives. Here, the underlined part is-

"where he lives" is a noun clause in this sentence.
Because It functions as a noun and provides additional information about the person being referred to.
- শুরুতে, where দেখে অনেকে মনে করেন এটি adverbial clause , কিন্তু আদতে তা নয়।

Noun Clause:
A noun clause is a clause that functions as a noun in a sentence. Noun clauses usually start with words such as "what," "how," "that," "whether," "if," etc. and provide additional information about a person, place, thing, or idea in the sentence. For example:

- What he said was surprising.
- How she did it is a mystery.
- That she is coming to the party is great news.