Questions & Answers about Tôi đọc về cáo.
Here về means about.
So:
- đọc = to read
- đọc về = to read about
- cáo = fox / foxes
So Tôi đọc về cáo is literally I read about foxes or I read about the fox, depending on context.
Vietnamese word order here is very straightforward:
- Tôi = I
- đọc = read
- về cáo = about foxes
So the pattern is:
Subject + verb + preposition phrase
That makes Tôi đọc về cáo a natural structure for I read about foxes.
If you changed the order, the meaning would change or the sentence might stop making sense.