Learn Spanish (Spain): La ceremonia es organizada por la academia. - The ceremony is organized by the academy.

In this passive voice structure, the past participle (organizada) acts like an adjective describing the subject. Because the subject la ceremonia is feminine and singular, the participle must match its gender and number perfectly.

Why do we use es instead of está for "is" in this sentence?

We use a form of the verb ser (es) because this sentence focuses on an action being performed by an agent (the academy). If we used está, it would describe a resulting state or condition (the ceremony is ready or set up), rather than the action of someone organizing it.

Why do we use por instead of para here?

In passive sentences, por is always used to introduce the agent, which is the person or group actually doing the action. If you used para, it would mean the ceremony was organized "for" the academy (as a recipient), which changes the meaning completely.

Is it common to use this passive structure in everyday spoken Spanish?

It is completely correct, but this type of passive voice sounds quite formal or journalistic. In casual spoken Spanish, people usually prefer the active voice and would simply say La academia organiza la ceremonia.