What should I use to generate PDFs from templates?

It depends on what kind of “templates” you mean and how much control you need.

Good options by use case

1. HTML/CSS templates → PDF

• Best for: invoices, reports, letters, emails turned into PDFs
• Use:
  • Puppeteer / Playwright (render HTML in a real browser, then print to PDF)
  • wkhtmltopdf (older, simpler)
• Pros: easiest if your templates are already web-based
• Cons: can be a bit heavy; print CSS quirks

2. PDF form templates

• Best for: filling out an existing PDF with fixed fields
• Use:
  • pdftk
  • Apache PDFBox
  • PyPDF / pypdf plus form tools
• Pros: preserves exact layout
• Cons: less flexible if you need dynamic layout changes

3. Word/Docx templates → PDF

• Best for: business docs created in Word
• Use:
  • docxtpl (generate DOCX from template) + LibreOffice conversion to PDF
  • Commercial SDKs if you need reliability at scale
• Pros: familiar authoring workflow
• Cons: conversion quality varies

4. Code-first PDF generation

• Best for: programmatically generated documents
• Use:
  • ReportLab (Python)
  • iText (Java/.NET)
  • PDFKit / Hummus-style libraries
• Pros: full control
• Cons: more work than HTML templates

My usual recommendation

• If you want template-driven PDFs with lots of design freedom: HTML/CSS + Puppeteer/Playwright
• If you need fill-in-the-blanks on an existing PDF: PDF form tools
• If you want structured business docs and already use Word: DOCX templates + conversion

If you tell me:

1. your language/framework,
2. whether your templates are HTML, Word, or PDF,
3. and whether you need headers/footers, page breaks, or tables,

I can recommend the best specific tool.