Currently I am using Zapier, Webmerge, and several types of form builders to populate a fillable PDF form. It is necessary for the pdf to have several of the fields filled in with "N/A" if the fields are otherwise left blank after the information inputed via the form builders is piped through Zapier and Webmerge.
Using Adobe Acrobat Pro DC I have opened the fillable PDF I've used with the Webmerge and clicked on Prepare Forms > target form field > Options Tab, and then typed N/A into the default field. This does not bring about the necessary result.
// Custom Format script
if (!event.value) event.value = "N/A";