Could you tell me where your office is located? or Could you tell me where your office located is?
Definitely is located. Unless you're trying to sound like Yoda.1
In questions with this structure, if there's a final object, it comes after that verb. You can say "could you tell me where your office is?", but if you want the word located in there, it goes after the is.
1: Now I wonder what Yoda talks like in foreign language dubs.
Could you tell me where your office located is
In English the verb usually comes right after the subject. The only words that go between the subject and the verb are adverbs for example, usually, always, often etc. For example,
I often walk in the park
The kind of formation existing in your second sentence corresponds to German language but not English.
Could you tell me where your office located is?
is not at all idiomatic, it sounds as if one is showing a character in a novel whose native language is Germanic or Slavic, and who does not know English well.
If "located" is omitted
Could you tell me where your office is?
is perfectly natural.
There is no absolute rule that a verb be last in a question in English, as I believe there is in some other languages.
Where are you going today?
Why do you want to do that?
What is the price of gas?
How do i get to the park.
All are very normal questions, and none have a verb at the end.