How to Stamp a PDF on iPhone, iPad & Mac (Free, No App Needed)

Someone emails you a PDF that needs your company stamp, and you’re away from your desk. On a phone it feels like you need a paid app for this. You don’t. Between Safari, the Files app, and Preview on the Mac, every Apple device you own can already stamp a PDF.

This guide covers three methods: our free browser stamper (works the same on iPhone, iPad, and Mac), Markup in the Files app, and Mac Preview. Then it covers how to keep the stamp sharp, and how to store it so you’re never rebuilding it from scratch.

Quick answer: On iPhone or iPad, open the PDF & Word Stamper in Safari, pick your PDF from Files, choose a stamp, tap where it goes, and download. On a Mac, paste a transparent PNG into the PDF in Preview, then Print → Save as PDF.

Which Method Should You Use?

If you only remember one thing: Markup is for handwriting, the browser stamper is for stamps.

First, Get Your Stamp as a Transparent Image

Every method below needs a stamp image. If you don’t have one yet, make it in the free Stamp Studio (it runs fine in Safari on iPhone):

1. Pick a starting design from the templates, such as a round company seal or a PAID / RECEIVED status stamp.
2. Edit the text, border, and ink color.
3. Tap Export, choose PNG, keep the background transparent, and pick 4x Print or 6x Ultra.

Transparency matters. A JPG always has a solid background, so it covers the text under it with a white box. A transparent PNG lets the words show through the gaps, the way real ink does. Our SVG vs PNG vs PDF guide explains when each format is the right one.

Already made a stamp in the Studio? If you open the PDF Stamper in the same browser, your last Studio design shows up in the stamp list as “My Custom Stamp”, so for Method 1 you don’t need to export anything.

Method 1: Browser Stamper in Safari (No App, No Upload)

This is the fastest route on iPhone and iPad, and it’s identical on a Mac. It’s also the only method here that places a real stamp image on iOS without installing anything.

On iPhone or iPad:

1. Open onlinestampgenerator.com/pdf-stamper in Safari.
2. Tap the upload area and choose Browse to pick your PDF from the Files app, iCloud Drive, or a connected service like Google Drive or Dropbox. Word .docx files work too.
3. Choose your stamp from the Stamp menu: one of the built-in seals and status stamps, or My Custom Stamp from the Studio.
4. Set the size. Pick 30, 40, 50, or 60 mm. 40 mm is the standard round company seal. The size is real-world, so it prints at that size on A4 or US Letter.
5. Set the tilt. The default −5° looks hand-pressed. Set it to 0° for a perfectly level mark.
6. Go to the right page with the ◀ ▶ arrows and tap where the stamp should sit. Overlapping the signature line slightly looks natural.
7. Tap Download Stamped Document. Safari asks to download the file; it lands in Files → Downloads as yourfile-stamped.pdf.

From there, use the Share button to email it, send it in WhatsApp, or save it back to iCloud Drive.

Why this is the safest option: the PDF is read and stamped inside Safari. There’s no upload step because there’s no server involved, so contracts and invoices stay on your phone. The stamp is drawn into the page itself (flattened), so the recipient can’t select it and delete it the way they could with an annotation.

Pro Tip: Rotate your iPhone to landscape before you tap to place the stamp. The page renders larger, so it’s easier to hit the exact spot on a crowded signature block. On iPad, the full page fits on screen in either orientation.

For the full desktop walkthrough, including flattening and signing order, see how to stamp and sign a PDF in your browser.

Method 2: Files App Markup (Initials, Dates & Signatures)

The Files app on iPhone and iPad has a built-in Markup tool. It’s excellent for handwriting on PDFs, but it isn’t designed for placing image files.

How to use it:

1. Open the Files app and tap your PDF to preview it.
2. Tap the Markup button (a pen tip in a circle).
3. Tap + to add Text, a Signature, or Shapes. The pen tools let you write directly on the page with your finger or Apple Pencil.
4. Tap Done. Files saves the changes into the same PDF.

What it’s good for:

• Initials on every page of a contract
• A handwritten date next to a stamp you placed with Method 1
• A drawn signature you saved once and reuse (Markup remembers it)
• Ticking boxes or circling a total

What it’s not good for: a company seal or an APPROVED stamp. Depending on your iOS version, Markup may not let you insert a PNG at all, and what it adds are annotations that sit on top of the page. Many PDF editors let the recipient move or delete them.

Combine the two: Place your company stamp with the browser stamper first, then open the downloaded PDF in Files and add your initials and the date with Markup. You get a real stamp plus a handwritten touch.

If you’d like your actual signature as a stamp image instead of a finger-drawn one, our signature stamp guide shows how to turn a pen signature into a transparent PNG.

Method 3: Mac Preview (Insert Image, Resize, Export)

Preview has no “Insert image” menu item, but it accepts pasted images, which works just as well.

1. Open your stamp PNG in Preview. Press ⌘A (Select All), then ⌘C (Copy).
2. Open the PDF in Preview and scroll to the page you want to stamp.
3. Press ⌘V. The stamp appears in the middle of the page as a movable object.
4. Drag it into place and resize it using the corner handles. Hold Shift while dragging a corner to keep the circle round.
5. Flatten and save. Choose File → Print, then in the bottom-left PDF menu pick Save as PDF. This bakes the stamp into the page.

Why print instead of just saving? A plain ⌘S keeps the stamp as an editable annotation, which anyone with Preview can click and delete. Save as PDF from the print dialog gives you a flattened copy. Keep your original file separately in case you need to redo it.

Don’t have a transparent PNG? Preview can make one. Open your stamp image, choose Tools → Instant Alpha (or the magic-wand icon in the Markup toolbar), drag across the white background, and press Delete. Then File → Export as PNG. It works on clean scans; for a crisp result, exporting a transparent PNG from the Stamp Studio is still better.

Want exact physical size? Preview resizes by eye, so a 40 mm seal can easily end up 55 mm. If size matters (company seals in India, Russia, or Indonesia often follow a convention), use the browser stamper’s mm setting instead. See company stamp sizes by country.

Keeping Stamps Sharp on Retina Screens & Print

Apple screens are 2x or 3x density, and printers want 300 DPI or more. A stamp that looks fine on a laptop can look fuzzy on an iPhone or a printout.

Rules of thumb:

• Export bigger than you need. Shrinking a large image stays sharp; enlarging a small one never does.
• Don’t screenshot your stamp. A screenshot captures screen resolution and an opaque background. Export it properly.
• Avoid sending the PNG through Messages or WhatsApp to yourself. Some chat apps compress images and may drop transparency. Use AirDrop or iCloud Drive.
• The browser stamper renders every stamp at 3000 × 3000 px before placing it, so Method 1 is sharp by default.

Saving Your Stamp for Reuse

You’ll stamp more than one PDF, so store the stamp somewhere you can find it in five seconds.

• iPhone / iPad: save to Files, not Photos. Tap the exported PNG, then Save to Files and pick an iCloud Drive folder like Stamps. Files keeps the PNG exactly as it is; going through Photos and other share sheets can sometimes convert it to JPG or HEIC and lose the transparency.
• Mac: keep a Stamps folder in iCloud Drive. It syncs to your iPhone and iPad automatically, so the same file works in all three methods.
• Keep the SVG too. If you ever want a physical rubber stamp, the SVG is what the stamp maker needs.
• Don’t rely on the browser alone. The “My Custom Stamp” shortcut lives in your browser’s local storage. Safari can clear website data for sites you haven’t visited in a while, and Private Browsing never keeps it. Export a file as your permanent copy.

Security note: A stamp image of your company seal, especially one combined with a signature, can be copied by anyone who gets the file. Keep it in your private iCloud Drive, not a shared album or team chat.

Common Problems and Fixes

That last row catches a lot of people. Adding a stamp changes the PDF, which breaks any certificate-based signature already on it. Our digital signatures vs digital stamps guide explains why.

Final Thoughts

You don’t need a paid app to stamp a PDF on Apple devices. On iPhone and iPad, the browser stamper in Safari is the quickest way to put a real, flattened stamp on a page, and Files Markup is ideal for the initials and dates around it. On a Mac, Preview’s copy-and-paste plus Save as PDF does the job. Whatever you use, start with a high-resolution transparent PNG and keep it in iCloud Drive so it’s ready on every device.

Stamp Your PDF Now

👉 Open the free PDF & Word Stamper: works in Safari on iPhone, iPad, and Mac. Pick a stamp, tap to place it, and download a flattened PDF. Nothing is uploaded.

Need a stamp first? Design one in the Stamp Studio or start from a ready-made template, then export a transparent PNG or SVG.