What is the ruling on working as a delivery person for a postal company that transports packages containing违禁 (violations of Islamic law), or as a driver who transports goods for the operation of usurious banks?

If you know or strongly suspect that the packages you are transporting contain prohibited items, such as alcohol, then it is not permissible for you to transport them. This is because it constitutes aiding in sin, based on the Almighty's saying: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." However, if you know nothing about it, there is no blame, as the default rule for things is permissibility. Nevertheless, it is better for a Muslim to avoid what makes him doubt, as the Prophet (peace be upon him) said: "Leave what makes you doubt for what does not make you doubt."

Regarding usury (riba), if what you are delivering is related to usury, then it is not permissible to deliver it, based on the saying of the Prophet (peace be upon him): "Allah has cursed the one who consumes usury, the one who pays it, the one who records it, and its two witnesses," and he said: "They are all equal." But if it is not related to usury, then there is no harm.