Use Adobe Acrobat: Open the app, go to Tools, select Combine Files, add the PDFs, arrange them, and click Combine
Use Preview on Mac: Open one PDF, show thumbnails, drag in the other PDFs, then save as a new file
Use Microsoft Edge or a browser PDF tool with an online merge feature
Use a free online PDF merger: Upload the PDFs, merge them, and download the combined file
Use a desktop PDF editor such as Foxit PDF Editor, PDF-XChange Editor, or Nitro PDF
Use command-line tools like PDFtk, Ghostscript, or qpdf
Use Python with libraries like PyPDF2 or pypdf to merge PDFs programmatically
Use Google Drive or OneDrive with a PDF add-on or connected app that supports merging
Use mobile PDF apps that include a merge or combine option
Check the page order before merging and save the final file with a new name