I'll jump in and mention a method I've used to prepare a few PDF tax forms (think information only filings) with the help of Alteryx. First I created a PDF template using the "Prepare Forms" tool in Acrobat by converting the existing tax form into fill-able form PDF. When you do this initially, Acrobat will assign a name to each line/box where it thinks you will want to key data. You can rename, add your own lines, etc. Once I have the fields I need on the form, I export the PDF data as a txt file. This gives me what I need for to create the import template using Excel. An important note, this only works if you organize your data (entity name, FEIN, tax year, etc) all on a single row per entity. The goal is to create a spreadsheet (basically a table) with the PDF form field names (gathered from the PDF export) as headings on row 1, then beginning on row 2, entity1 and its data across the columns, then entity2 and its data, and so on. Once this is done, an Alteryx workflow is used to create a csv file for each row of data while maintaining the headings. So if you have 15 entities, you end up with 15 csv files ready to import into your PDF template you've created. (In Acrobat: Prepare Form > More Options > Import Data)
Obviously this isn't as automated as using a python script or similar but it is a way to automate part of the process for the lay person like myself. It's worth noting that this may not work well with complex tax forms so your mileage may vary.
As far as the Alteryx workflow I use, I found it as a response on Community. If you are interested, let me know and I'll see if I can find the source.
TLDR: Create PDF template with existing tax form. Use Alteryx to create csv files to import into said PDF template.
