PDF forms are flexible, quick and easy to build, and, provided they are built properly, highly accessible. However, if you are testing a PDF form for accessibility, there are a couple of notable JAWS bugs to be aware of.
Date picker: JAWS 2020
The first of these is that the current version of JAWS (JAWS 2020) no longer works properly with the PDF date picker. Older versions of JAWS work fine with it, as does NVDA. Just not JAWS 2020.
Fortunately, this doesn’t mean that you need to avoid using the date picker altogether, as the end user can still manually type a date into the relevant field. However, it would be useful (not to mention less confusing to those testing PDF forms) if this bug could be ironed out in the next JAWS version.
Check boxes and forms mode
A potentially much more serious and consequential problem with JAWS and PDF forms is its inability to escape forms mode from a check box. As should be the case, you can escape forms mode from a text field by pressing either the Esc key or the Number pad + key, or by using the arrow keys. However, none of these options work for check boxes in PDF forms (they do, of course, in HTML forms).
This is a long-standing problem which goes back as many JAWS versions as I can remember (with variations). It would be really helpful if JAWS could be fixed so that it works the same way as it does in HTML forms in this respect. Imagine the frustration, for example, of being unable to escape forms mode to read a supplementary piece of information when trying to complete a multiple-choice exam paper or a long or complex questionnaire.
In all other respects both JAWS and NVDA work well with properly constructed, accessible PDF forms. However, fixing these two issues, especially the forms mode issue, would be very much welcomed.