How to write a condition to enter a value if field is empty in Document Designer

Summary

Write a condition to enter a value if field is empty in Document Designer

Content

Hi,

We created a document through Document Designer. There is a field in our document "NTN/CNIC" it is also mapped with an attribute on Transaction Level.

We want to write a condition in Document Designer that whenever "NTN/CNIC" attribute is empty, a statement should print on Document (This is a mandatory field, please enter details).

I attached a screenshot for better understanding. Is it possible it achieve?

Appreicate if someone can support us to write this condition.

Thank you,

Regards.

Version

21A Patch8