Questions & Answers about Sobre ito.
Not necessarily. Filipino often uses a predicate-first word order. In this sentence, sobre names what the thing is, so it comes first: Sobre ito.
This kind of order is very common in short identifying statements, especially after a question like Ano ito? meaning What is this?
There is no separate word for is here. Filipino can make simple equational or identifying sentences without an overt copula.
So even though Sobre ito looks very short, it already means This is an envelope. English requires is, but Filipino often does not.