Question was how to create fillable pdf using pandoc: https://np.reddit.com/r/haskell/comments/mj7kv5/monthly_hask_anything_april_2021/gt8pcsk/
Source: https://github.com/NixOS/nixpkgs/issues/14463#issue-145858361
NIX_PATH=nixpkgs=http://nixos.org/channels/nixpkgs-unstable/nixexprs.tar.xz nix-shell --pure -p "(texlive.combine { inherit (texlive) scheme-small hyperref; })" pandoc
NIX_PATH=nixpkgs=http://nixos.org/channels/nixpkgs-unstable/nixexprs.tar.xz nix-shell --pure -E 'with import <nixpkgs> { }; stdenv.mkDerivation {name = "otf"; buildInputs = [pandoc (texlive.combine { inherit (texlive) scheme-small hyperref; })];}'
(both work)
So to create Forms PDF from the markdown file, do: