1. If you're asking a direct question, the correct form is this: "What is his destination?" This is the interrogative form, where the verb ( 'is') has to come before the subject ('his destination'). 2. If these four words are part of a longer sentence, either an embedded or indirect question, you use the affirmative form. In the affirmative form, we put the subject before the verb. For example: I'll ask him what his destination is. We need to know what his destination is. Can you tell me what his destination is? I hope that helps.

What is his distination Because this is question and verb to be get before the noun in question

What is his destination ?