If optional values are not provided, what value should be filled in the send email activity?

In the context of a send email activity within Mendix, if optional values are not provided, it is appropriate to fill the field with an empty value. This signifies that the optional field does not have a value assigned to it, allowing the system to proceed without any erroneous assumptions about the missing information. Leaving a field empty indicates that the operation should continue without that particular data, whereas other options like "Null" or "N/A" might imply something different, potentially leading to confusion in processing.

Using an empty value is a clear and straightforward indication that the user has consciously chosen not to provide data in that specific field, thus maintaining clarity and simplicity in handling optional parameters during the email-sending process. It ensures that the application does not treat the absence of a value as an error or a default choice, which might happen if other suggestions were used.