how long does it takes to recieve bridging visa?

My partner is on a tourist visa to Australia and she have to leave next week on wednesday 4th of July, We will be applying for the Partner visa (subclasses 820 and 801), I was wondering after we apply online and made the payment of $7000 does she automatically switch over to the bridging visa? Do we have to apply for the bridging visa separately and how long does it takes to receive the bridging visa as after 4th of July she can no longer remain in Australia legally.