Through, by way of: thông qua

Thông qua means "through, by way of": it names the channel, the means or the activity through which something happens. It goes before a noun, or việc + a verb: Người dân có thể nộp hồ sơ thông qua cổng dịch vụ công. Residents can submit their documents through the public services portal.

Compare bằng, which names a tool, a vehicle or a language used directly: trả bằng thẻ (pay by card), đi bằng xe buýt (go by bus). Thông qua is for a route or a go-between: a website, an agent, a programme, a process. Tuyển dụng thông qua phỏng vấn (recruit through interviews). Plain qua does the same job and is the usual word in speech: mua qua mạng (buy online), biết qua bạn bè (hear about it through friends).

Thông qua has a second meaning you'll see in every report from a parliament or council: "pass, approve" a law, resolution or plan. Hội đồng nhân dân tỉnh đã thông qua nghị quyết về học phí. The provincial People's Council has passed a resolution on school fees. Here it's the main verb, and the document comes straight after it.

So look at the position. After the main verb, followed by a channel, it's "through". After the body that decides, followed by a law or plan, it's "pass".

You'll meet both in news, government texts and papers (thông qua khảo sát, through a survey). In conversation, plain qua is more natural: Tôi biết chỗ này qua một người bạn. I found this place through a friend.