Why is a bill stuck in "draft" status?

draft means the bill hasn't been Sent yet — that's the action that posts the GL journal and moves it onwards. The usual reasons it's still sitting there: a required field is missing (supplier, total, lines), the three-way match against a linked PO failed, or it's waiting on someone in the approval policy. Open the bill — the action banner at the top of the detail page names the blocker. Fix what it tells you and click Send.

See: finance-three-way-match.