You can import Invoices via following steps:
Step 1: Income > Invoice > New Invoice / import
Step 2: Download the sample CSV file and make sure that you have adjusted all your invoice details as per sample file given in the software. You can also see the tips mentioned while importing the Invoices such as-
> Fill exact same name of customer, item name and warehouse as per your ProfitBooks account. If the name is not found in your account, then the new customer will create automatically.
> If customer is new, then fill GSTIN field.
> Place of supply is mandatory for Indians.
>If invoice is export invoice, then fill shipping port code, export bill no. and export bill date.
Step 3: Select the file you want to import and click on import.