The integration with Quickbooks works by passing daily sales and cost of goods sold data to Quickbooks.

Sales get pushed to a receipt endpoint. The sales data is pushed based on this article:

For every tax present on the order, it adds a separate item to the sales receipt and attaches items referencing payment accounts to make

the total of the receipt $0.

The integration creates a separate Quickbooks account for every tax rate and payment method in POS.

To enable it, you need to enable 'Quickbooks integration' setting in General settings and link each location to a QB instance in Settings -> API keys & integration.

It'll start passing the data the next day after being linked.

Also, a starting date can optionally be set if you go to Settings -> Locations and edit the location. When it's set, it'll start syncing sales data starting from that date. That is useful if you want it to only pass sales data starting from a certain date.