It depends on where you were when you ordered. If you were physically within the bar when you ordered, you can use either. If you were somewhere else and you ordered by phone or by an app, you can only use "from."

One more thing: If the British use "takeaway" the same way we use "takeout" in the US, then it's uncountable and shouldn't have the indefinite article "a" in front of it.

You would say: I ordered takeaway from/in a bar close to the office. From if you had it delivered and in if you went into the bar yourself. Hope this helps :)

Agreeing with Jonathan that US vs British applies here in terms of "takeout" vs. "takeaway" and there would not be "a" with either. Also agreeing that if you were placing the order AT the location and waiting for it, it would be EITHER "in a bar close to the office" or "from A bar close to the office". Either way, it's "a bar" If you placed the order from a location other than that bar and had to go to get it, it would be "from a bar close to the office".

Just to clarify British vs American usage - in the UK I would always say, "I ordered a takeaway" and that is definitely the common usage. I've never heard anyone in the UK say, "I ordered takeaway".