Does God create creatures eternally, or does He create them when the reasons for their existence, which humans take, are present? And is destiny eternal?

A distinction must be made between al-qadar (divine decree) and al-maqdoor (that which is decreed). Al-qadar is eternal, while al-maqdoor is temporal and renewed. Al-qadar is defined terminologically as what Allah's knowledge has preceded and what the Pen has inscribed concerning the destinies of creation before their existence, and things occur in accordance with this decree. It encompasses two matters: Allah's eternal knowledge of everything that will come into existence and its attributes, and the inscription of that in the Preserved Tablet, then the bringing into existence of what Allah has decreed in the manner that His knowledge preceded and His Pen inscribed, so the reality corresponds to the inscribed knowledge.