I think the full sentence is "we got it approved" Please correct me if I'm wrong and another question why approved (adj) comes after it (noun)?
get is a stand-in for many other verbs, among them: become, receive, buy (purchase), be
- I got approval. I received approval.
- I got a letter today. I received a letter today.
get is also used instead of be:
- I got approved. = I was approved.
- I got fired. = I was fired.
was/get approved is not adjectival. It is a passive construction:
I got approved [by x to do y]. For example.
get approved is more colloquial and be approved is a bit more formal.
It's not an adjective here, but a passive participle.
It's using the complex verb pattern "get something verb-ed", which is effectively a causitive passive:
They got a house built.
She got him promoted.
This seems to be a blend of the get-causitive (eg "I got him to tell me about it") and the get-passive (eg I got promoted).