How to sign a PDF sent by email
Quick answer: To sign a PDF sent by email, save the attachment to your device, open it in a PDF editor such as Quick PDF, tap Sign and add your drawn, typed or uploaded signature, then download the signed copy. Reply to the original email and attach the signed file so it stays in the same conversation.
Sign in with Google or email and start editing. Saving your file starts a free trial: 7 days on yearly ($29.78/yr) or 2 days on monthly ($2.99/mo). Cancel anytime. 🔒 Your file stays on your device.
The PDF is sitting in your inbox with a short note: "Please sign and send back." The tricky part is not the signature; it is getting the file out of the email app, signed, and back into a reply. This guide shows exactly how to do that from Gmail, Outlook and Apple Mail on a phone or computer.
You will also see how to avoid the most common mistake: sending back the original unsigned attachment.
Sign an email attachment and reply with Quick PDF
- Save the PDF attachment On a computer, click the attachment's download icon. On iPhone, open the attachment, tap the share icon and choose Save to Files. On Android, tap the download icon on the attachment.
- Open the saved PDF in Quick PDF Go to quickpdfapp.com, sign in, and open the file from Downloads or the Files app.
- Fill in anything else the sender asked for Type into form boxes, or use Add text for names, dates and blank lines on flat forms.
- Tap Sign and place your signature Draw, type or upload your signature, tap the signature line, and resize it to fit.
- Download the signed PDF Tap Download. Give the file a clear name, such as the original name plus "signed", if your device asks.
- Reply and attach the signed copy Go back to the email, tap Reply, attach the signed PDF from Downloads or Files, and send. Or use Share in Quick PDF to start a new message instead.
Saving the attachment in each email app
| Email app | How to save the PDF |
|---|---|
| Gmail on a computer | Hover over the attachment and click the download arrow; it goes to Downloads |
| Gmail app on iPhone | Open the attachment, use the share or more menu, then save it to Files |
| Gmail app on Android | Tap the download icon on the attachment; it goes to Downloads |
| Apple Mail on iPhone or iPad | Tap the attachment, tap the share icon, choose Save to Files |
| Outlook on the web or desktop | Open the attachment's menu and choose Download (or Save as) |
| Outlook app on a phone | Open the attachment, then use the share or download option to save it |
Menu names move around between app versions, but the idea is the same everywhere: get the PDF saved to your device first. A preview inside the email app cannot be opened by another app.
Reply in the same thread, or share a new message?
Quick PDF's Share button opens your device's share sheet, so you can send the signed PDF through Mail, Messages, WhatsApp or Drive in one step. That creates a new message, which is fine for a quick send.
If the sender is handling many documents, replying inside the original email thread is often better: they see the context, and the signed file sits next to their request. To do that, Download the signed file, go back to the email, tap Reply and attach it from your Files or Downloads.
Either way, open the attachment in your sent message once to confirm it is the signed version.
The mistake that sends an unsigned copy
The most common problem: you sign the document, then reply and attach the original file, because it has the same name and sits right next to the signed one. To avoid it:
- Rename the signed file (for example, add "signed" to the end) when your device lets you.
- Check the time on the file when attaching: the signed copy is the newest one.
- On a phone, look at the attachment preview in your reply before sending; your signature should be visible on the page.
When the email asks for more than a signature
- Initials on every page: create a short initials signature and place it in each box.
- A date: use Add text beside the signature. See how to add a date to a PDF.
- Checkboxes and fields: tap them on a fillable form, or type an X with Add text on a flat one. See fill out a PDF form and save it.
- A file that is too big to send back: see PDF too large to email.
- Personal details like an SSN or bank account: think about the safest way to send it; see send a PDF securely.
When an email signing link is better
Some senders do not attach a PDF at all. They send a link from an e-signature service that asks you to click through and sign online. If you got a link like that, use it: the sender is collecting signatures with an audit trail, and a separately signed PDF may not be recorded in their system.
Quick PDF is for the other case: a plain PDF attachment that you sign yourself and return. It places an electronic signature image on the page. It does not send documents out for signature, does not keep an audit trail and does not create certificate-based digital signatures. This is general information, not legal advice: electronic signatures are generally valid in the US under the ESIGN Act and UETA, but if the sender asks for a specific method, follow it.
Troubleshooting
I cannot find the PDF I saved
On iPhone, open the Files app and look in Recents or the folder you chose. On Android and computers, check Downloads.
The attachment is a Word document, not a PDF
Quick PDF works with PDFs and photos; it does not convert Word files. Ask the sender for a PDF, or save it as PDF from a word processor first.
The PDF is password-protected
If the sender gave you the password, use Unlock to remove it, then open the unlocked copy and sign it. Unlock only works when you know the password; it does not bypass unknown passwords.
Questions people ask
How do I sign a PDF attachment in Gmail?
Download the attachment from Gmail, open it in Quick PDF in your browser, tap Sign and place your signature, then download the signed copy. Reply to the Gmail message and attach the signed PDF.
How do I sign a PDF from email on my iPhone?
In Mail, tap the attachment, tap the share icon and choose Save to Files. Open quickpdfapp.com in Safari, open the file from Files, tap Sign and draw your signature, then download it and attach it to your reply.
Can I sign a PDF directly inside my email app?
Some email apps offer a basic markup tool for attachments, which can add a drawn signature. For typed or uploaded signatures, filling form fields and adding text, save the attachment and open it in Quick PDF.
Why did the person receive my document unsigned?
Usually the original attachment was sent instead of the signed copy. Download the signed version, give it a different name, and check the preview in your reply before sending.
Does the sender need Quick PDF to open my signed PDF?
No. The signed file is a normal PDF that opens in any PDF reader, browser or phone.
Is a PDF signed this way legally valid?
In the US, electronic signatures are generally valid for most documents under the ESIGN Act and UETA, with exceptions such as wills and some notarized or court documents. This is general information, not legal advice; check with the sender if unsure.
Do I have to pay to use Quick PDF?
You can open a PDF and edit, sign or fill it after signing in with Google or email. To download, print or share the finished file you start a subscription with a free trial: 7 days on the yearly plan ($29.78 per year) or 2 days on the monthly plan ($2.99 per month). You are charged when the trial ends unless you cancel, and you can cancel anytime.
Sign in with Google or email and start editing. Saving your file starts a free trial: 7 days on yearly ($29.78/yr) or 2 days on monthly ($2.99/mo). Cancel anytime. 🔒 Your file stays on your device.