Save

The save process is handled by the add-on. No additional code needs to be added.

Save message

To change the default success message, use the model's save_message property in the init() method, like this:

// Namespace and use statement...

class Settings extends Model
{
    // Class properties...

    protected function init()
    {
        $this->save_message = __( 'Hooray! Settings have been saved!', 'my-domain' ); 
    }
}

Errors and validations

Use field options validate_callback and validate_message, as described in the field options article, to apply custom validation and reporting.