Learn French: Est-ce que vous allez au Maroc ?

Because Maroc is a masculine country. In French, we use au (which is a blend of à and le) to say 'to' or 'in' before masculine countries that start with a consonant. If it were a feminine country, like France, you would use en (en France).

What exactly does Est-ce que mean here?

It doesn't translate word-for-word into English. Instead, placing Est-ce que at the very beginning of a sentence is a common way to turn a normal statement into a yes-or-no question. It changes vous allez (you are going) into 'are you going?'.

Where is the word for 'are' in 'are you going'?

French doesn't use a separate word for 'are' in this context. The single verb allez covers both 'go' and 'are going'. So, vous allez translates to both 'you go' and 'you are going'.

Could I use tu instead of vous for this question?

Yes! If you are asking a friend or someone you are close to, you would say Est-ce que tu vas au Maroc ?. You use vous allez here either because you are talking to more than one person, or you are speaking formally to one person.