The migration process is a one-time support. To migrate your data from Zoho Invoice, you need to login to your Zoho Books account. The migrated data of Zoho Invoice would be moved to a new organization in Zoho Books. Below, are the steps to help you perform the migration process.
The import process would take some time and once completed, you'll receive a confirmation mail. For help on this, you can check the video
Zoho Invoice FAQ