odoo/odoo/addons/base/models/ir_ui_view.py", line 592, in raise_view_error
raise ValueError(message)
ValueError: Field `invoice_is_snailmail` does not exist
Error context:
View `n/a`
[view_id: n/a, xml_id: n/a, model: n/a, parent_id: n/a]
I check in my code invoice_is_snailmail this files written in files but still odoo though an error
The field invoice_is_snailmail is a field in standard Odoo module snailmail_account. If you want to use this field in your custom module, you need to install snailmail_account module first.
Best practice is to list the dependent module snailmail_account as a dependency in your module so that Odoo will install it automatically. More info on module definition and depends can be found here: https://www.odoo.com/documentation/13.0/reference/module.html, see manifest field depends.