Question

Tell me where is the pen. correct it

Answer 1

Tell me where the pen is.

The sentence structure should follow the format :

Subject   verb   object

But when a sentence is changed into a question the format becomes :

verb   subject   object

Likewise here , the statement is an indirect speech of a question and so the verb should come at the end.

Answer 2

Heya...
it could be your answer...

MAY I KNOW WHERE IS THE PEN.

Hope it HELPS...