How-to guide
How to sign a document sent by email
"Please sign and return" doesn't require a printer, a scanner, or an account with a signing service. Whatever arrived in the attachment — PDF, Word file, or a photo of a form — you can sign it on the device you're reading this on and send it straight back.
Before you start: you'll need your signature as an image. The signature for PDF tool prepares the transparent signature you'll place on the document — free, no account, and nothing you type leaves your browser.
The 'please sign and return' problem, solved properly
It's one of the most common requests in working life: a document arrives as an email attachment with "please sign and return". The old answer — print, sign, scan, attach — takes fifteen minutes, needs hardware most homes no longer have, and produces a blurry third-generation copy. The modern answer takes about three minutes, produces a cleaner result, and works from a phone.
The universal recipe has three parts: get the attachment into an app that can place an image on it, place your prepared signature, and return a PDF — always a PDF, whatever arrived — in the same email thread. Each step has one important detail: download rather than preview (previews are read-only), keep one good transparent PNG of your signature that you reuse forever, and reply in-thread so the request and your signed response stay attached to each other as context.
The steps below branch by what arrived: PDF (most common), Word document, or a photo/scan of a paper form. If the sender instead sent a link to a signing service like DocuSign or Adobe Sign, stop here — just follow their link; the service captures your signature inside its own flow and none of this is needed.
Step by step
Save the attachment
Download the attachment rather than previewing it in the email window — previews are often read-only. Note the format: PDF and Word cover almost every case.
Prepare your signature once
Create your signature and download the transparent PNG. You'll reuse this same file for every document anyone ever sends you, so it's worth making it look right.
If it's a PDF
Open it in Acrobat Reader, Preview, Edge, or your phone's markup tools and place your signature over the line. The full walkthrough for each app is in how to add a signature to a PDF.
If it's a Word document
Insert the PNG with Insert → Pictures, set wrapping to In Front of Text, and drag it onto the line — details in how to insert a signature in Word. Then export to PDF before returning it, so your signature can't be casually edited out.
If it's a photo or scan
Open the image in your phone's photo markup (iPhone: Edit → markup pen; Android: Google Photos → Edit → Markup) and sign directly, or insert both the scan and your signature into a blank Word page and export to PDF.
Reply with the signed copy
Attach the signed file to a reply in the same email thread rather than a fresh message. The thread preserves the request and your response together — useful context if the agreement ever matters later.
Troubleshooting
The attachment opens read-only
You're in the email client's preview. Download the file first (usually a download arrow on the attachment chip), then open it from your Files/Downloads folder in an app that can edit.
The sender needs it 'today' and I only have my phone
That's enough: download the attachment, open it in Files (iPhone) or Drive (Android), tap the markup/annotate pen, place your signature, and share the result back into the email thread — all standard OS features.
The scanned form arrived sideways or skewed
Rotate before signing: phone photo editors and Preview/Photos rotate losslessly. Signing a crooked scan and returning it crooked reads as careless even when the signature is fine.
My returned file is huge (10+ MB)
Photo-based PDFs balloon. Use the export/print-to-PDF step rather than attaching raw photos — it typically compresses to a fraction of the size, and many mail servers reject very large attachments.
Best practices
- Make your signature PNG once and store it where both computer and phone can reach it (Drive, iCloud, Dropbox) — future requests become two-minute tasks.
- Rename the returned file clearly: 'Lease-Agreement-signed-JSmith.pdf' beats 'document(3).pdf' for everyone downstream.
- If the document has multiple signature spots (initials each page, sign last page), do initials as a second, smaller PNG — Acrobat's Fill & Sign stores both.
- When stakes are higher, add one sentence in the reply: 'Signed copy attached; I agree to the terms as sent on [date].' It reinforces intent and dates the agreement in writing.
Common questions
Is replying with a signed PDF legally acceptable?
In most everyday situations, yes — the signed document plus the email thread showing you returned it demonstrates intent and attribution, the two things that matter most. Formal exceptions (notarized documents, wills) are covered in our legality guide.
The sender used DocuSign or a similar service — do these steps apply?
No — just follow the link in their email. Signing services capture your signature inside their own flow. These steps are for plain attachments where the sender expects a signed file back.
Should I send back a Word file or a PDF?
PDF. A returned Word file can be edited by anyone, including your signature. Exporting to PDF freezes the document as you signed it.
What if they explicitly ask for a 'wet signature'?
Then they want ink on paper — print, sign, and either post it or scan the signed page. Some documents (notarized forms, certain leases, government filings) legitimately require it; our legality guide lists the categories.
Can I forward the signed document to someone else instead of replying?
You can, but reply to the requester first — the thread is your shared record. Forward separately if a third party needs a copy.
Do I need to sign every page?
Only if asked. Common conventions: full signature on the signature page, initials on each preceding page when the sender marked initial-lines. When unsure, ask — signing pages that weren't meant to be signed creates confusion too.