"Did you order beer?"

Translation: Kamu memesan bir?

[Speedy12846]

You need apakah if it is a question.

[WayangOrang]

In the pure formal style, yes.
But it's not really necessary.
In everyday speech, you can simply change the intonation to make it a question.

You ordered beer ?
Did you order beer ?

[Gill714966]

I keep having trouble with this. I understand how it works but I’m answering in writing so surely it needs question mark at least?

[Mario_Fez]

A question mark would indicate it as a question, yes. But this app seems to focus on vocabulary and word order, not so much on punctuation.

You would need to add a question mark in writing, but you don't need to for the sake of Duolingo's lessons