how make all the fields read only if it has data with document action "document will save"

Check the values of hte fields. When the field is not empty set the property readonly.

Use this line for each field to be locked:

this.getField("NAME").readonly = true;

You should place this script in a button action, not in a "Doc will save" event.

Hey there,

Even if this has been asked before, we'd be happy to answer again.

If you are the creator/owner of form and working with Acrobat DC, then you can make the changes in PDF form's properties and set its form fields as read only.

Open PDF forms in Acrobat DC>right click on form field>Properties>General>Read-only>Close

For detailed information, please refer to this help article: https://helpx.adobe.com/acrobat/using/pdf-form-field-properties.html#general_tab_for_form_field_properties

Thanks,

Akanchha