Questions & Answers about Он заказал пиво.
Заказал is the perfective past form, so it means he ordered the beer as a completed action.
- Он заказал пиво. = He ordered a beer / He placed the order.
- Он заказывал пиво. = He was ordering beer / He used to order beer / He ordered beer at some point (with focus less on completion and more on the process or fact)
In this sentence, the speaker is presenting the action as a single completed event, so заказал is the natural choice.