What's inside a QBO file
A QBO file is structured text listing transactions — date, amount, description, and a transaction type — plus account and institution details. It's not meant to be read by hand; QuickBooks parses it on import.
How to import a QBO into QuickBooks
In QuickBooks Online, go to Banking → Upload from file and select the QBO. QuickBooks Desktop uses File → Utilities → Import → Web Connect Files. QuickBooks matches the account and lists the transactions for review.
The INTU.BID bank ID
Every QBO carries an INTU.BID — Intuit's identifier for the bank. If QuickBooks shows an 'unsupported financial institution' warning, the INTU.BID isn't recognized; set your bank's ID before exporting and the warning clears.
Creating a QBO from a statement
You can generate a QBO from a bank statement PDF, or convert an existing OFX/CSV/QFX export to QBO. Review the transactions first, set the INTU.BID if needed, then import.