QBO allows you to invite up to 2 Accountants/Bookkeepers into the file without them counting towards the user limit of the subscription.
In order to do this, from the Gear Icon in the top right corner, go the Your Company Menu -> Manage Users..
You will then have the option at the bottom of the screen to invite additional Bookkeepers/Accountants into the file.
Happy Collaborating!
Updated: March2017