• Make sure you have fully reconciled your bank account(s) up to year end and confirm that your ending book balances agree with your bank statement balances.
• Verify that all customer invoices have been entered and approved.
• Confirm that you have entered and agreed all vendor bills.
• Validate all expenses, ensuring their accuracy.
• Corroborate that all received payments have been entered and recorded accurately

Refer this Odoo documentation about the year end,