"Excuse me, where can we exchange money?"

Translation: 请问，我们可以在哪里换钱？

[Han336780]

Can you say 请问，我们在哪里可以换钱?

[afam101]

That would actually be the most natural construction according to Chinese Grammar Wiki: https://bit.ly/2D6UU1Z
Prepositional phrases + verb + object
There are too many errors on Duolingo Chinese, personally I have given up on it.

[Dr_Jerry]

Yes, it's perfectly acceptable even though Duo inexplicably marks it wrong.

[yession]

I agree. It is perfectly fine to a native speaker.

[QSLN13]

或者 请问，我们哪里可以还钱 不对吗

[whoapanda]

Could you say 我们那里可以换钱？

[DaveLommen]

Well, for one thing, you have the wrong "na" (na3 li3 means where, while na4 li3 means there).

[Cinnamon5230]

我们哪里可以换钱 is acceptable. But it is not a translation.

[QSLN13]

He means 在. Is it ok to not use 在 it in this sentence