In questions, the noun or pronoun follows the verb.
If the sentence is not a question, the noun or pronoun should precede their verb.
He is here.
Is he here?
So, is "what <was> the content" a question?
It is not a question. It's just a part of the sentence "Can you please..." which is a question itself. The position of 'was', then, should be at the last so that it will follow it's noun "the content."
Also, another sentence you used is "Can you please tell me where should I put was?"
It should be "where I should put was" because it is not a question. Your real question there is "Can you please tell me...?"
The words what and where confuses us. We should keep in mind that these words are not used as interrogative words.
Where am I? a question. I want to know where I am. not a question
I hope I didn't make it even more confusing. I'm not a native speaker of English xD.