I'm currently in the process of developing a new custom payment provider for Odoo. As part of this development, I've added the necessary fields for the provider's credentials to the configuration page. However, I'm encountering an issue where the fields I've added are not visible on the page. Consequently, when I attempt to save the configuration, I receive an error due to a required field not being filled in.

I'm seeking assistance to understand why the fields (postpay_merchant_id, postpay_live_api_key, postpay_test_api_key) I've added are not visible on the configuration page and how to resolve this issue. Any insights or suggestions would be greatly appreciated. 

Thank you in advance!