Thank you James. How do you export to csv?

From your Accounting menu (Reporting), choose the report that you want to see, we'll choose General Ledger. Once you pull any report, there is a big green button at the top of the report that says "EXPORT (XLSX)". Or, you can use the "SAVE" button to generate a .pdf instead.

By default it will probably show you the current month only, but you can change the date range to anything you want. For a year-end, you would choose "This Financial Year". This also gives you the numbers your accountant needs to open your new books.

You should pull EVERY financial report this way at every year end - it should be part of your year-end/period-end process.

For a full close-out of Odoo, I would do this for every report and set the date range using the "Custom" option to pull everything from the first day I used Odoo to the last. This gives you a full record of everything you ever did in Odoo accounting. In theory, you could use this to completely reenter all data into your new accounting system (but you wouldn't).

In total, the entire process might take you five minutes and then you have a full record for your accountant.