if you want to integrate Zoho with QBO , you can use zapier...so basically when you create an invoice in zoho ...it will then also create an invoice in QBO ...can also be done with estimates contacts etc etc.

why do i know this ...because the estimating and invoicing features in QBO ...really lack ...ie they are atrocious...Zoho invoice/books completley blows QBO out of the water

if you simply want to export your existing zoho invoices.....use a .csv file exported from zoho ...change the columns in the zoho to match that of QBO ...and hit import ...in QBO

now the extra problem with this is the cost....you will have a minimum of 20 bucks/ month for zapier...and the cost of your zoho books account + the QBO account