We have a payment log for ACH and wires with approximately 800 line items each month. Also tons of JEs with multiple lines. I want to purchase a third party software to upload into QB Online. I called the support desk but not much help, they referred me to the apps store. I tried to use the IIF template but something when wrong and the JE upload duplicated my Account numbers and I don't know why. There are so many vendors but I need advise on which app to chose. Can anyone help? Thanks.
First and foremost, a warm welcome to the QuickBooks Community. We're happy to have you and hope you can learn from and share expertise through conversations with other QBC members.
File uploads and templates are a tricky business. The large majority of apps in the QuickBooks App Store are designed for QuickBooks Online only. There are, however, a handful of apps available for the Desktop version. Here is a link to the store. If you are working from a CSV file, there is a free data transfer app called Dynamic Ventures General Journal Entry that might be useful.
I hope this helps, and thank you @Rustler for your awesome recommendation.