Yes, you may import your contacts from Invoice2go. I'd be glad to show you the steps below:
Export your contacts from Invoice2go as .xlsx (Excel file).
Once done, log in to QuickBooks and go to the Settings.
Choose Import Data, then select Customers. (This depends on what file you really want to import.)
Click the Browse button to open the data in QuickBooks. You may also check the sample file by downloading it, to ensure the data from Invoice2go is categorized properly.
After getting the file from your computer, select Next.
Categorize the details then click Next.
Verify the customers’ information if it's correct, you may select Back to edit it or Import to finish the process.
I've added a sample screenshot below for your additional reference.