I have a pdf with multiple form fields and a program to populate them, I would to disable users from entering anything into these fields, what should I do? Also, I want to keep the option of letting user create new form fields (if needed), I have tried to use the PDFileSecurity class and it doesn't seem to do exactly what I want, please advise, thanks.
As per your requirement, Aspose.Pdf.Kit is a component which can used to accomplish your requirement.
Once the data is populated in fields you can use FlattenField(…) method of Form class to flatten any particular field or use FlattenAllFields(….) method to flatten all the fields over the form.
Or
If you need to make any particular field to be disabled from entering information into it, you can use SetFieldAttribute method of FormEditor class and set the field as ReadOnly.