PDF fields (AcroForm) natively associated with OCG (layers) via the /OC key in the annotation dictionary, with dynamic toggling of the layer state. Target: pdfLaTeX + Adobe Acrobat/Reader.

• Native binding of fields to layers: adds /OC <ref> to the widget dictionary.
• Dynamic layer toggle via /SetOCGState action.
• Simple API:
  • ocgform (environment): defines the OCG context for fields.
  • \OCGTextField (command): text field bound to the current OCG.
  • \OCGToggle and \OCGToggleButton: link/button to show/hide dynamically.

• Engine: pdfLaTeX
• Viewer: Adobe Acrobat/Reader (other apps may ignore /OC on annotations)
• LaTeX packages: hyperref, ocgx2, acrotex (provides eforms), xparse, l3packages

• Local (same folder as the .tex):
  • \usepackage{./ocgformfields} (harmless warning about name difference).
• MiKTeX TEXMFHOME (persistent):
  • Create: C:\Users\<user>\texmf\tex\latex\ocgformfields\ocgformfields.sty
  • MiKTeX Console → Settings → Directories → Add… add C:\Users\<user>\texmf
  • Tasks → Refresh file name database
  • Verify: kpsewhich ocgformfields.sty

\documentclass{article}
\usepackage[a4paper,margin=2.5cm]{geometry}

\usepackage{hyperref}
\usepackage{ocgx2}
\usepackage{eforms}
\usepackage{ocgformfields}

\begin{document}

\OCGToggle{sens}{\textbf{Show/Hide sensitive data}}

\begin{ocgform}{Sensitive Data}{sens}{on}
  Name: \OCGTextField[name=name,width=8cm]{}\\
  Email: \OCGTextField[name=email,width=8cm]{}
\end{ocgform}

\medskip
\OCGToggleButton{sens}{Toggle Sensitive Data}

\end{document}