Once you have identified and drawn in the appropriate form input fields, you will need to add this data to the tagged structure of the PDF document.
Perform a "Find" within the Tags Palette for "Unmarked Annotations". This will search for your input fields you previously drew.
Once these input fields are identified, create a Form tag and position the Form tag at the correct location within the tag hierarchy.
Yes, you can make a PDF form accessible, but it will take time and familiarity with PDF forms in general to complete the process.