If you're in doubt, this means you suspect it's wrong. Try a little harder to make it right. This is a passive construction. Let's start with the non-question form - The singer released this song last year = This song ..... released last year. What is the missing word here? I'll give you a clue. It's the verb 'to be'. What tense should it be in? Present? Past? Future? This will help you correct your question.

When was this song released. or... When did this song get released The second sentence is incorrect, these are a couple of examples that might be better. If you are unsure that what you are doing is correct, ask someone. If you think you are doing something wrong, just ask someone.

"When was this song released?"