Short answer: share one of your PDFs to Grabio, tap Merge PDFs (open PDF24), then on the PDF24 page pick all your PDFs and tap Merge. The merge itself happens on PDF24’s servers, not on your iPhone.

Scanned pages, signed forms, a few receipts you need to send as one attachment: combining several PDFs into one file comes up constantly. Grabio’s PDF menu gets you to a free merge tool in a few taps from the share sheet, with no account.

How to merge PDF files on iPhone with Grabio

At a glance

How to Merge PDF Files on iPhone
Cost
Free, forever
Account
None needed
App Store
No install
Runs on
iPhone, via Shortcuts
  1. Add Grabio to your iPhone once. It is a free Apple Shortcut: get the free Shortcut here.
  2. Open one of your PDFs in the Files app or Mail and tap the Share button.
  3. Scroll down the share sheet and tap Grabio.
  4. Grabio recognises the PDF and shows the PDF menu. Tap Merge PDFs (open PDF24).
  5. Grabio shows a short note: your PDFs are in Files, and on PDF24 you tap Choose Files, pick your PDFs, then Merge. Tap through and PDF24 opens in your browser.
  6. On PDF24, tap Choose Files and select every PDF you want, including the one you shared. Then tap Merge and download the combined file.

Grabio does not pre-select your file on the PDF24 page. You choose the files there yourself.

What the Grabio PDF menu offers

Menu item What happens
Merge PDFs (open PDF24) Opens PDF24 in your browser; you pick the files there
Compress PDF See compress a PDF
PDF → Images Turns pages into images
Convert PDF (open VERT) Opens VERT in your browser
Save to Files Keeps the PDF in Files

Source: Grabio v56 shortcut menu list.

Is it private and free?

Merging is the one PDF job here that does not run on your iPhone.

PDF24 says on its merge page (read 9 Nov 2026): “PDF files are merged in the cloud on our servers”, “Files are automatically deleted from the PDF24 server after one hour”, “PDF24 is free of charge” and “No registration required”. It also says it is free thanks to advertising, so expect ads on that page.

Grabio itself asks for nothing here. If you would rather not upload a document at all, do not use this route for sensitive files.

Merge PDFs on iPhone: FAQ

Why does this open a website instead of merging on my phone?

Grabio hands this one job to PDF24 rather than doing it inside the Shortcut. PDF24 states that it merges on its own servers.

Is the file I shared already selected on PDF24?

No. Grabio’s note says your PDFs are in Files, and you pick them with Choose Files on PDF24.

How long does PDF24 keep my files?

PDF24 says files are deleted from its server after one hour (merge page, read 9 Nov 2026). That is PDF24’s statement, not something Grabio controls.

Related on iPhone: scan a document or receipt to PDF, compress a PDF, crop a PDF, or PDF & Document Tools.

Video downloading is the other half of what Grabio handles for free, see the full video downloader for iPhone comparison if that is ever what you need next.