How do I invite into Liquid a Vendor who I have in QuickBooks?

If there are Vendors in your QuickBooks Online account that you would like to add to Liquid you'll navigate to the QuickBooks Vendors tab of the Vendors List (within Settings).

From there, you can press Add to Liquid to invite the Vendor. You'll press Confirm to open up the Add Vendor workflow for this Vendor.

While the Vendor name will be prefilled, you will have to fill out all other fields to send the invitation.