My self Paul Bryant work for DancingNumbers company which users to migrate any accounting software data to QuickBooks Desktop or QuickBooks Online.
Converting data from FreeAgent to QuickBooks Online involves exporting your data from FreeAgent, typically in CSV or Excel format, and then importing it into QuickBooks Online. Key data to transfer includes customers, suppliers, invoices, bills, and bank transactions. It's essential to review and clean your data before importing to ensure accuracy. QuickBooks Online offers a step-by-step import tool to facilitate this process, but you may also consider using third-party software or seeking professional help to ensure a smooth transition.
https://www.dancingnumbers.com/quickbooks-data-conversion/freeagent/