How to sign a password-protected PDF on iPhone

You were sent a PDF to sign, and your iPhone won’t cooperate. Maybe it demands a password before it shows you anything. Maybe it opens perfectly and then the Markup tools sit there greyed out, refusing to let you put a signature anywhere.

Those look like the same problem. They are not, and almost every article on this topic mashes them together — which is why the fix you found didn’t work.

Spend thirty seconds working out which one you actually have.

Which lock are you dealing with?

Open the PDF in Files (or tap the attachment in Mail) and watch what happens.

Case A — it asks for a password before showing you the document. The file is encrypted. Nothing on your phone can read a single page of it until the correct password is typed in. This is a user password, sometimes called an open password.

Case B — the document appears immediately, but you can’t annotate it. Markup opens and the signature tool is unavailable, or your signature refuses to drop onto the page, or a signing app reports the file as protected. Nothing asked you for anything. This is a permissions restriction — the file carries flags saying “viewing: yes, editing: no”, enforced by an owner password you were never meant to see.

Case A is about access. Case B is about permission. They need different answers.

Case A: it won’t open without a password

The honest scope of this page first: this works when you have the password — the sender texted it to you, it’s in the second email, it’s your own date of birth because that’s how your bank sends statements. If you don’t have it, there is nothing here for you, and nothing in any other article either. Encryption is doing exactly its job. Go and ask the sender for the password. That is genuinely the whole answer.

With the password in hand:

1. Open it

In Files, tap the PDF, type the password, tap OK. It opens. That alone may be all you needed — if Markup works from here, skip ahead and sign it.

2. If you’ll need it again, make an unlocked working copy

The password sticks to the file, so every app you hand it to will ask again, and some will simply refuse the file outright. Making one unencrypted copy for yourself saves a lot of friction:

With the PDF open and unlocked, tap Share → Print.
Let the preview thumbnail render. You don’t need a printer connected to anything.
Tap the Share button on the print preview screen (on older iOS versions, pinch outward on the thumbnail first).
Choose Save to Files.

What comes back is a fresh PDF, re-rendered from what the print system saw, with no password attached. It’s the same mechanism behind flattening a signed PDF on iPhone, and it carries the same honest tradeoffs: fillable form fields, clickable links and bookmarks usually don’t survive it, and a scan-heavy document may shift slightly in size or sharpness. If the document still has fields you need to type into, don’t do this yet — open it, fill it, then re-save.

On a Mac, if there’s one nearby: open the PDF in Preview, enter the password, then File → Export as PDF with the encryption option left unticked. Cleaner, and it keeps the text layer intact.

Keep the original either way, until you’ve checked the copy is right.

Case B: it opens fine but won’t let you sign

This is the “signature greyed out” problem, and it frustrates people far more than Case A because nothing appears to be wrong.

The PDF was exported with editing disabled. It happens deliberately (a company standardising its outgoing paperwork) and it happens completely by accident (someone’s export preset had “restrict editing” ticked three years ago and nobody noticed). Either way the file says don’t annotate me, and well-behaved apps — including Apple’s own Markup — obey it.

You have two reasonable moves.

Ask the sender for a signable copy. Unglamorous, but it’s the right first step, and it’s often a thirty-second fix on their end. If someone locked a document against editing and then asked you to sign it, that’s usually a mistake they’d want to know about. It also matters when the restriction was intentional: re-rendering a document that someone deliberately locked, and sending it back as though it were the original, isn’t a great look on a contract.

Or re-render your own copy. The same Print → Share → Save to Files route from Case A produces a flat, unrestricted PDF you can annotate freely. This isn’t cracking anything — permission flags are a request to viewer software, not encryption, and printing is a permission you already have. But apply the same judgement: you’re producing a new file, which is fine for a form you were asked to fill in, and less fine for a controlled document.

Then sign it, and — this matters here — send back a copy where the signature is genuinely part of the page rather than a draggable sticker, which is what the print-to-PDF route gives you anyway.

Now sign it

Once the file opens and accepts annotations, it’s an ordinary PDF and the ordinary options apply.

Free, built in: iOS Markup. Tap the PDF, tap the pencil icon, then + → Signature, draw one with your finger, drag it onto the line, tap Done. For a single form that’s the end of the story and you don’t need anything else — the full walkthrough is here.

If this keeps happening: documents that arrive locked tend to arrive locked repeatedly — HR packets, bank forms, landlord paperwork. That’s the case where a signing app stops being a luxury. In Signed, you make your signature once (draw it properly, type it in a handwriting style, or generate one), import the PDF, and drop your saved signature, initials and the date wherever they belong. The export is flattened by default, so the copy you send back can’t lose its signature at the recipient’s printer.

Two things worth knowing while you’re here:

Signed is local-first — the document is processed on your iPhone and never uploaded. Given that the files in this situation are the encrypted ones — bank statements, contracts, medical paperwork — handing them to a website that offers to “unlock your PDF” for you is the one route on this page nobody should take. You’d be uploading the sensitive document and typing its password into someone else’s server.
You can try the signature part before installing anything, with the free signature generator in your browser.

What none of this does

Straight, so nobody wastes an afternoon:

It does not open a PDF whose password you don’t have. No app, site, or trick on your iPhone does. Ask the sender.
It does not strip encryption from a file you can’t already open. Every step above starts from a document that’s already unlocked on your screen.
Re-rendering is one-way. The new copy has no annotation layer and usually no form fields — keep the original.
None of this is a statement about the document’s legal standing. Removing a password changes what your software will let you do; it doesn’t change what the document requires of you. If it’s high-stakes, check what that document type actually needs before you send it back.