Why can't I type in a PDF on my iPhone?

You tap the PDF. You tap the empty box where your name is supposed to go. Nothing happens. No keyboard, no cursor, no sign the phone even noticed.

The reason this is so maddening is that four completely different problems produce that exact same nothing — and most of the advice you’ll find online only fixes one of them, which is why the last three things you tried didn’t work.

Here’s how to tell them apart.

Ten seconds of diagnosis

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

What you see	What’s wrong	Jump to
It opens, but tapping the blank line does nothing	The PDF has no form fields — much the most common case	Case 1
It opens, but Markup tools are greyed out or refuse to stick	Editing is restricted	Case 2
It demands a password before showing you anything	The file is encrypted	Case 3
It only misbehaves inside one app (Gmail, Slack, a browser)	You’re in a preview, not an editor	Case 4

Case 1: there are no form fields to type into

This is the answer roughly four times out of five, and almost nobody says it plainly: the document you were sent isn’t a fillable form. It looks like one — there are lines, boxes, little grey rectangles — but those are just printed shapes. There is no invisible text box waiting behind them.

It happens because the file is a scan of a paper form, or because somebody exported it flat from Word, or because it was signed and flattened somewhere upstream. A real fillable PDF (an AcroForm) contains actual interactive fields; a picture of a form contains none.

You cannot type into a form field that doesn’t exist. What you can do is put your text on top of the page — which, for every practical purpose, gets you the same finished document.

The free way: iOS Markup

Nothing to install:

Open the PDF in Files (or tap the attachment in Mail).
Tap the Markup icon — the pen tip in a circle, top right.
Tap + → Text.
A box saying “Text” appears. Tap it → Edit → type what you need.
Drag it onto the line. Use Aa to set the size, and the colour dots to make it black.
Repeat for each blank. Tap Done, then Share to send it back.

If you’ve got a handful of blanks to fill, this is genuinely the whole answer and you should stop reading here. It’s free, it’s already on your phone, and the result is a normal PDF that anyone can open. There’s a longer walkthrough of this exact tool — sizing, alignment and the four things that stop it looking obviously typed-on — in how to add text to a PDF on iPhone.

Where it starts to hurt, honestly: every text box is placed and sized by hand, so a twelve-field form is twelve rounds of drag-pinch-squint. Sizes drift between boxes and it shows. Nothing you type is remembered, so the next form starts from zero. And on a dense page, nudging a box a millimetre at a time on glass is exactly as fun as it sounds.

The app way, if this happens often

Signed exists for the repeat case. You import the PDF, then drop the pieces you need — text, your name, the date, initials, a checkmark, your signature — tap by tap, and export a clean flattened copy. The parts that don’t change (your name, your initials, your signature) are saved once and reused on every document after that, so form number twenty takes about as long as form number two.

The documents never leave your iPhone — no upload, no account, no cloud copy of your paperwork. If you also need boxes ticked, that’s the same flow: adding a checkmark to a PDF form.

And if the PDF genuinely does have interactive fields — you tap one and a keyboard appears — then none of this applies and you’re better off in the fill out and sign a form on iPhone guide, which covers real form fields properly.

Case 2: the file is restricted from being edited

The document opens instantly, looks perfect, and then Markup won’t play: the tools are greyed out, or your text box simply won’t stay put.

Nothing asked you for a password, so this feels like a bug. It isn’t. The PDF carries permission flags that say viewing yes, editing no — often set deliberately by a company, and just as often set by accident by an export preset nobody has looked at since 2019. Apple’s Markup respects those flags, which is why it goes quiet.

This one has its own page, because the fix is a specific workaround rather than a setting: see Case B in how to sign a password-protected PDF on iPhone.

Case 3: it won’t open at all

If your iPhone demands a password before it will show you a single page, the file is encrypted and there is nothing to diagnose. No app on any phone can read it without the password — that’s encryption working exactly as designed.

If the sender gave you the password, the same guide covers it (Case A), including how to save one unlocked working copy so you don’t retype the password in every app.

If they didn’t, ask them. That really is the entire answer, and any tool promising otherwise is not being straight with you.

Case 4: you’re looking at a preview, not an editor

Tap a PDF inside Gmail, Slack, WhatsApp or a browser and you often get that app’s built-in viewer. Viewers render pages. They don’t edit them — some don’t even offer a Markup button, so there’s nothing to tap and no error to explain why.

The tell: the same file behaves differently depending on where you open it.

The fix is to get the file somewhere that can actually edit it:

Tap Share (or the download arrow) inside the app you’re in.
Choose Save to Files — Downloads is fine.
Open it from the Files app, and Markup will be there.

From Mail, you can skip the detour: tapping the attachment and then the Markup icon works directly. Gmail and Slack users have to go through Files. Once it’s in Files, you can share it into a signing app in one tap too — the same route as signing a PDF someone emailed you.

The short version

Blank lines that ignore your taps → the form isn’t fillable. Put text on top with Markup, or use an app if you do this regularly.
Greyed-out Markup → editing is restricted. Workaround needed.
Password prompt → encrypted. Get the password; nothing else works.
Only broken in one app → save to Files first.

One last honest note: none of this makes a document more official than it was. Typing your name onto a PDF is filling in a form, and what any particular document actually requires — a witness, a notary, a specific service — depends on the document and where you are. Here’s how we think about that.