This process is highly dependent on the requirements and estimates of each state, as each state has its own specific turnaround times (for example, Alabama has a turnaround of 58 business days).
On top of this, ZenBusiness also handles priority a bit differently, with the highest priority going to their Premium Package holders. Here are the estimated turnaround times, state-specifics aside:
Starter: 6-7 working days
Pro: 4-5 working days
Premium: 1-3 working days
While the premium might seem absurdly fast, keep in mind the state you choose to form in may throw a wrench in that estimation, and all ZenBusiness can control is how fast their own turnaround time with your paperwork can be. Regardless of this, ZenBusiness is perhaps the best LLC formation company in terms and speed and deliverability.