Sometimes we realise that we have done a mistake on the invoice for example by putting wrong customer etc. This tutorial will show you how to cancel the invoice in Odoo. Simple and free solution.
Install "Cancel Journal Items"
Firs of all you need to install App made by Odoo to allow cancelling the journal items.
Go to the Apps tab and search for "cancel" and then install.
Allow Cancelling Entries
Navigate to the Invoicing/Accounting Module and enter the configuration/Journals.
In the selected journal (for example "Customer Invoices") go to the "Advanced Settings" and check the "Allow Cancelling Entries".
If you can't see the setting make sure to activate the developer mode.
Cancel Invoice
The button "Cancel" will appear in the Odoo.
How to cancel invoice in Odoo
Cancel invoices in Odoo