How does sorcery enter a place where no one can reach it, and is that done by means of jinn?

The sorcerer places the material used in magic (threads, knots, papers,...) himself, or he asks the jinn or the magic seeker to place it in the bewitched person's house. The jinn have the ability to enter homes and place whatever the sorcerer commands them to. Sheikh al-Islam Ibn Taymiyyah mentioned that devils might bring stolen money, especially from traitors and those who do not mention Allah's name over it. Whoever fortifies himself with legitimate incantations (adhkar) and mentions Allah's name before every action will be protected from Satan.

The sorcerer may place the magic himself, as happened in the sorcery against Prophet Muhammad (peace be upon him), where a Jewish man hid the magic in a well.

If the magic is extracted and it contains knots, it should be untied while reciting (Qur'an), and what the sorcerer did should be destroyed, as Sheikh Ibn Baz clarified. One should beware of going to fortune-tellers and imposters.