Almost everything people install an app for on iOS is already there. The features are real, capable and hidden in unhelpful places.
Where each feature actually lives
| Task | Where | Not where you expect |
|---|---|---|
| Picture to PDF | Files app → Create PDF | Photos has no such option |
| Save a PDF you are viewing | Share → Save to Files | — |
| Scan a document | Notes → camera icon → Scan | Also in Files |
| Write or draw on a PDF | Files or Books → markup pen | — |
| Sign a PDF | Markup → + → Signature | Stored and reusable |
| Combine PDFs | Files → select → Create PDF | Merges in filename order |
The right-hand column is the whole problem. Photos is where your pictures are, so Photos is where people look for Create PDF, and it is not there. Save the images to Files first and the option appears.
Saving a picture as a PDF
- In Photos, select the image or images, tap Share, then Save to Files. Pick a folder.
- Open the Files app and go to that folder.
- Select the images — tap Select, then tap each one.
- Tap Share, then Create PDF. With one image the option also appears on a long press.
- The PDF is saved alongside the images, in filename order.
Filename order is alphabetical, not numeric, so IMG_10 comes before IMG_2. If the sequence matters, rename with zero padding first, or build the PDF somewhere you can drag the pages into place.
Scan, do not photograph
For anything that is a document rather than a picture — a form, a receipt, a letter — the scanner produces a far better result than the camera, and it is built into two apps you already have.
In Notes, tap the camera icon and choose Scan Documents. In Files, tap the three dots and choose Scan Documents. Both detect the page edges, correct the perspective, flatten the lighting and produce a clean high-contrast page.
The difference matters when the document is going somewhere official. A photograph of a form carries the angle it was taken at, the shadow of the phone and the surface it was resting on. A scan looks like a scan, and is far more likely to be accepted first time.
Writing and drawing on a PDF
Markup is built into iOS and available anywhere a PDF is displayed — Files, Books, Mail attachments, Safari downloads.
Open the PDF, tap the markup icon (a pen tip), and the toolbar appears: pen, highlighter, pencil, eraser, ruler, and a plus button for text boxes, signatures, shapes and magnification.
- On iPad with a Pencil, just start writing — markup activates automatically.
- Signatures are stored after the first time and reused with two taps.
- Text boxes are the right tool for filling in a form that has no real fields.
- Everything saves as annotations, so it can be moved or deleted later.
- Undo works with a three-finger swipe left, or shake to undo on iPhone.
Because these are annotations rather than page content, a reader that ignores annotations shows the original page. That is usually what you want for a marked-up draft, and worth knowing if you assumed a signature was permanently part of the document — flattening is what makes it so.
Filling in a real form
If the PDF has genuine form fields, iOS detects them and you can tap and type directly — no markup needed. The fields highlight when you tap the page.
If it does not, use markup text boxes. Set the font size once and it carries to the next box, which makes a long form much less tedious.
One caution for anything official: a form filled with markup text boxes is visually identical to a properly filled one but structurally different — the text sits on top rather than in fields. Some systems that read forms automatically will see an empty form. If a submission portal rejects a form you know you completed, this is usually why.
Where files go, and getting them off the device
Files saved to iCloud Drive appear on every signed-in device. Files saved to "On My iPhone" live only on that device and are included in an encrypted backup, not synced.
That distinction catches people out when a document seems to have vanished — it is usually on the other storage location rather than gone.
To move a PDF to a computer, AirDrop is fastest to a Mac, and iCloud Drive or an emailed copy works to anything else. For heavier work — merging dozens of files, compressing a large scan, splitting a long document — a browser on the iPad handles it, and browser-based tools that process locally keep the file on the device rather than uploading it.
Frequently asked questions
How do I save a picture as a PDF on iPhone?
Save the image to Files first, then select it in the Files app, tap Share and choose Create PDF. The option does not exist in Photos, which is why it seems to be missing.
How do I save a PDF on iPad?
Tap Share, then Save to Files, and choose a folder. iCloud Drive syncs to your other devices; "On My iPad" stays on that device only, which is where files usually are when they appear to have vanished.
How do I write on a PDF on an iPhone or iPad?
Open it in Files or Books and tap the markup icon for pen, highlighter, text boxes and signatures. On an iPad with an Apple Pencil you can simply start writing and markup activates by itself.
Should I photograph or scan a document?
Scan. Notes and Files both have a document scanner that detects page edges, corrects perspective and flattens lighting. A photograph carries the angle, shadow and background, and is far more likely to be rejected by whoever receives it.
Why are my images in the wrong order in the PDF?
Files builds the PDF in filename order, which is alphabetical rather than numeric — IMG_10 sorts before IMG_2. Rename with zero padding, or build the PDF where you can drag pages into position.
Why was my completed form rejected as empty?
Probably because it was filled with markup text boxes rather than real form fields. The text sits on top of the page instead of in fields, so a system reading the form automatically sees nothing. Check whether the PDF has genuine fields that highlight when tapped.
Can I combine PDFs on an iPhone?
Yes — select several PDFs in the Files app, tap Share and choose Create PDF. They merge in filename order. For control over the order, a browser-based merge tool lets you drag them into place.