Is it permissible to place translated copies of the Holy Quran in the private mailboxes of non-Muslims without their permission, by analogy with what companies do when they place their advertisements?

There is no objection to gifting a translation of the meanings of the Holy Quran to a non-Muslim, as it is one of the means of inviting them to Islam, unlike the Mus'haf which contains the Quranic text itself. It is not advisable to place the translation in mailboxes for fear of its desecration. The preferable approach is to use alternative means, such as stickers containing a link to websites introducing Islam, to avoid its dishonor and ensure it reaches those who are receptive. The translation of the meanings of the Quran is considered an interpretation and does not take the ruling of the Quran regarding its permissibility for a non-Muslim to touch it, or for a person in a state of ritual impurity (junub), a menstruating woman, or a disbeliever to read it. As for the Mus'haf containing the Arabic text, it is not permissible to allow a disbeliever to possess it, for fear of its defilement and desecration. However, it is permissible to write a few verses within a sermonizing message.