I'm creating custom fields and I have a technical question.
When I create the fields, I know that the specification is saved in the wp_post and wp_postmeta tables, so far so good, I have already located the configuration specification for the fields, but I cannot find the data that is saved in the field.
The data appears normally, but I'm curious to know where the data is saved!
What is the data that you want to know? The field value or field settings?
The field value (AKA post meta) is saved to the table wp_postmeta. The field settings are registered on page load and they are not saved to the database if you use the code to register the fields.
As I mentioned above, the field value is saved to the table wp_postmeta. You can access the database, table wp_postmeta, search for the meta key: field ID and you can see the associated post ID and field value.
Please read more about custom fields in the documentation https://wordpress.org/documentation/article/assign-custom-fields/