Sure, here is the passive voice of the sentence "Prime's availability caused major excitement among Gen Z customers":
Major excitement was caused among Gen Z customers by Prime's availability.
The active voice of the sentence is when the subject of the sentence performs the action. In this case, the subject is "Prime's availability." The passive voice is when the subject of the sentence receives the action. In this case, the subject is "Gen Z customers."
To change the sentence from active to passive voice, we need to make the following changes:
The subject of the sentence becomes the object of the sentence. The verb of the sentence is changed to the past participle form. A new subject is introduced, which performs the action of the verb. The preposition "by" is used to introduce the new subject.
I hope this helps!