Hi,

You can refer to this blog for additional information about how the journal was created.

https://www.cybrosys.com/odoo/odoo-books/odoo-book-v16/accounting/journals/

Hope it helps

When you register a payment in the Account Payment model in Odoo, the corresponding journal entries are created in the Journal Entries model. 

When you create or validate a payment in the Account Payment model, Odoo automatically generates accounting entries to record the payment. You can view these entries in the Journal Entries section. Additionally, you can see the related journal entry directly via the Journal Entry smart button on the specific payment record.

For more clarification, you may see aan attached screenshot: