Must one delete chat history at the request of the other party, and is the sender entitled to choose the recipient?

Chat or incoming message archives belong to the recipient, not the sender. However, the recipient should respond to the sender's request to delete them if the sender fears harm or corruption from their retention, or the recipient should clarify to the sender that they will keep them in a secure place. This is a requirement of brotherhood and maintaining affection. Otherwise, the recipient is not obliged to respond to the sender's request, as the sender has no authority over another person's device. Al-Shafi'i said to Al-Rabi' ibn Sulayman: "O Rabi', do not speak about what does not concern you. If you utter a word, it owns you, and you do not own it."