How to add a company stamp to a PDF on iPhone

A supplier wants the invoice “signed and stamped”. An agency wants the company seal on the form. You’re away from the office, the rubber stamp is in a drawer, and you have the PDF on your iPhone.

This is doable. It comes down to two jobs: getting a clean image of the stamp, then placing that image on the PDF so it stays where you put it. Most of the problems people run into, like a white box around the stamp, a stamp that won’t print, or a recipient who can drag it off, come from skipping part of the first job or forgetting the last step of the second.

Step one: you need a clean image of the stamp

Every way of putting a stamp on a PDF, free or paid, starts with an image file. If you don’t have one yet, make it once and keep it (the full version, with lighting, halo and colour checks, is in how to make a digital copy of your company seal on iPhone):

1. Press the stamp on plain white paper. Use fresh ink and press evenly, and do a few so you can pick the best one.
2. Photograph or scan it in good, even light. The document scanner in Notes or Files (tap the camera or ••• menu, then Scan Documents) flattens the perspective and evens the lighting, which helps a lot.
3. Crop tight around the impression.
4. Remove the paper. This is the step that matters. A photo of a stamp is a red or blue stamp on a white rectangle. Put that on a PDF and the white rectangle covers the text and lines under it. You want a transparent PNG, where only the ink is kept.

There’s a full walkthrough of the transparency part in how to make a transparent signature PNG. It works exactly the same for a stamp. One thing to watch: stamps often have thin rings, small text and pieces that don’t touch each other, and some background-removal tools quietly drop those. Zoom in and check the whole seal survived before you use it.

You don’t need a $20+ “seal maker” app if you already own the physical stamp. Those apps design a new seal for you, which is a different job from copying the one your company actually uses.

The free route: Markup, with honest limits

The built-in Markup tool (open the PDF in Files, tap the pen icon) is great for signatures, text and shapes. Stamps are where it gets awkward:

• The Signature tool only takes a drawing. You can’t import an image into it, so a seal can’t be saved there.
• On recent iOS versions, the + menu in Markup has an “Add Sticker” option. If you’ve made a sticker from your stamp image (in Photos, touch and hold the stamp, then tap Add Sticker), you can place it on the PDF. Whether you see this option depends on your iOS version and the app you opened the PDF in, so check your own device and don’t assume it’s there.
• What Markup adds is an annotation. It sits on a layer above the page. Until the file is flattened, it can fail to print, look different in another viewer, or be moved or deleted by whoever opens the file next.

If you go this way, finish by flattening the PDF. The Print → Share → Save to Files trick in how to flatten a signed PDF on iPhone bakes the stamp into the page for free.

On a Mac: Preview can’t insert an image straight into a PDF either, but you can copy your transparent PNG, paste it onto the open PDF page, then resize it and drag it into place. Export or print to PDF afterwards so it’s flattened.

Placing the stamp with Signed

If you stamp documents every week, rebuilding the sticker-and-flatten routine each time gets old. This is the job Signed handles:

1. Add your seal once. In Signatures, go to Seals and scan the stamp with the camera or import a photo of it. Signed cleans up the background but keeps the ink’s original colours (a red seal stays red; it isn’t recoloured like a signature would be) and keeps the small detached marks that make up most seals.
2. Open the PDF you need to stamp, from Files, Mail or anywhere you can share a PDF from.
3. Tap the Seal tool and drop your seal on the page. Pinch to size it, drag it into place, and add it to as many pages as you need.
4. Add the rest if the document asks for it: your signature, the date, a name or a title.
5. Tap Finish. The PDF you share is flattened, so the stamp is part of the page and prints the way it looks on screen.

It all happens on the phone. Signed doesn’t upload your documents, which matters when the thing you’re stamping is an invoice, a contract or company paperwork.

Getting the stamp to look right

• Size it like the real thing. Most physical company stamps are about 3–4 cm across. An oversized seal looks fake and a tiny one looks like a smudge.
• Overlap the signature slightly, if that’s the custom where you are. Some places expect the seal to sit partly over the signature, others want it beside it. Copy whatever the paper version usually looks like. (For a personal seal rather than a company one, see how to add a hanko seal to a PDF on iPhone.)
• Don’t cover important text. A transparent PNG helps, but dense ink over a figure or a date can still make it hard to read.
• Check the exported file, not just the editor. Open it again, zoom in, and make sure the rings and small text are crisp.

What a stamp image does — and doesn’t — prove

It’s worth being straight about this part.

A stamp image on a PDF shows the document was marked with your company’s seal. It doesn’t prove who put it there, because anyone with a copy of the image could do the same. It’s a picture, not a cryptographic digital seal or a certificate. Keep your seal image somewhere private, just as you’d keep the physical stamp locked in a drawer.

Whether a stamped PDF is accepted depends entirely on who receives it and what the document is. Many businesses are happy with a stamped scan, some want the original paper, and some documents need extra formalities whatever the stamp looks like. If you’re not sure, ask the recipient what they accept before sending. The general picture for signatures is in are electronic signatures accepted?. Signed is a tool for marking documents, not legal advice.

The short answer

Make a clean, transparent PNG of your stamp first, because that one step prevents most of the problems. Then either place it for free with Markup (as a sticker on recent iOS versions) and flatten the PDF afterwards, or use a signing app with a proper seal tool, which places the stamp in its own colours and exports a flattened file in one go.