To quickly locate, via artist-mode the spot to be filled in a pdf, view via pdf-tools https://github.com/Nidish96/cart.el as dummy handwritten fonts I like:
\usepackage{pbsi} % for most text except all-caps
\usepackage{fontspec} % for all-caps, require XeLaTeX o LuaLaTeX
\usepackage{pifont} % for check marks
\usepackage{xcolor} % for a dummy ink color
\newcommand{\blue}[1]{\textcolor{blue}{#1}} % as a handy wrapper
usable like, for as much pages as you need (a \clearpage between them)
% block for page 1, repeat the block for 2, ...
\begin{tikzpicture}[remember picture,overlay]
\node at (current page.center) {\includegraphics[page=1]{ToBeFilledPDF}};
\begin{scope}[shift={(current page.south west)},every node/.style={anchor=base west}]
\node at (50mm,237mm) {{\blue{\bsifamily normal text}}};
\node at (29mm,170mm) {{\blue{\fontsize{12}{13}\selectfont\bsifamily scale text size as needed}}};
\node at (62mm,199.7mm) {{\blue{\ding{51}}}}; % a checkmark
\node at (135mm,24mm) {\includegraphics[scale=1]{signature.png}};
\node at (1mm,2mm) {{\blue{\fontspec{QTChanceryType}\bfseries ALL CAPS}}};
\end{scope}
\end{tikzpicture}
where coordinates came out from cart.el wizard-clicks, then eventual small change by hand to perfectly align. It's not super quick, Xournalpp is quicker, but via LaTeX you can input anything, with very nice dummy handwritten fonts, you can add images if needed (for instance insurances form at least in Italy/France) etc. Next step is eventually make them (a bit long) a PDF/A, adding an eventual vector version of the signature, adding an eventual PADES signature or even embedding the LaTeX source into the pdf, just to teach a lesson to those who in the 2024 still send non-fillable pdf forms meant to be printed, filled by hand, scanned back...
