Who normally builds and installs the decorative framing around windows?

Per my other question posted today, we’re replacing our exterior windows. The windows are currently surrounded by siding, which we want to remove and replace with stucco. When we do this, I think we’ll also need to add some decorative framing around the windows. Is this something we should order with the windows? Or is it handled separately by a carpenter or other specialist?

The trimmer!

Our finish carpenters usually take care of that