Sunnah include a great etiquettes regulating the lives of people, being bound by these Sunan saves Muslims from many evils, and serious problems; of these etiquettes is seeking permission on entering people’s homes, and it must be very clear and explicit so that the homeowner have the chance of acceptance or rejection of the visit. If one of us knock on the door and the owner of the house asked: who is there? We should not reply by saying: I am! Because that response in most does not disclose the personality of the knocker, therefore, the homeowner may have to open the door while not knowing the visitor, or even bothers himself in speculation and conjecture.

Accordingly, it was the sunnah of Prophet Muhammad, peace be upon him, for the visitor to identify himself on seeking permission for entering where Jabir (May Allah be pleased with him) reported: I went to the Prophet (PBUH) and knocked at the door (to seek permission). He asked, "Who is there?) I said: "I). He repeated, ) I, I?!) as if he disliked it.  [Al-Bukhari and Muslim].

There are other instances in the sunnah of the Prophet where the knocker identified himself, and accordingly the Prophet was pleased for that. Al-hakim related, Adh-Dhahabi ranked it authentic, on the authority of Buraidah who said: I was at the mosque while Abu-Musa Al-Ash`ari was reciting the Glorious Quran, the Prophet went out asking: Who is this? Buraidah replied: It is me Buraida, may I be sacrifice for you O Prophet of Allah! The Prophet said: this has been given from the Psalms of David)

It is also related by Al-Bukhari on the authority of Um-Hani` bint Abi-talib who said: I went to the Prophet on the opening year, I found him bathing while Fatimah shielding him, he said: who is this? I replied: I am Um-Hani`.

This is the sunnah to identify oneself in clarity, however if the name is not identifying enough, he shall identify himself by attribute or anything may completely identify his personality. This would give the homeowner the chance to accept visit or reject it which is his absolute right, and also it maintains the sanctity of our homes.

https://en.islamstory.com/en/artical/28787/266-Sunnah-of-not-saying-I