How to sign a PDF on iPhone and Android
To sign a PDF on Android, open it in an app such as PDFriend, tap the menu, then tap Annotate and sign. Tap Signature, tap the page, draw your signature one time and tap Save. Drag the signature to the line, then save the PDF. The app keeps the signature on your phone, so the next PDF takes one tap. For a form with fields, use Fill form first. The iPhone app has the same steps.
How do you sign a PDF on your phone?
PDFriend has a Signature tool in its PDF viewer. You draw the signature with your finger and put it on the page. The app does the work on your phone, so the PDF does not go to a server. These steps take about one minute.
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Open the PDF
Open PDFriend and tap the PDF in the file list. A PDF in an email or a download also works: tap it, choose Open with, then choose PDFriend.
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Open Annotate and sign
In the PDF viewer, tap the menu (three dots), then tap Annotate and sign.
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Draw your signature
Tap Signature, then tap the page. Draw your signature in the box with your finger, then tap Save. The app keeps the signature for later use.
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Place the signature
The signature shows in the middle of the page. Drag it to the signature line. Pinch to make it larger or smaller.
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Save the signed PDF
Tap the Save button at the top. The app saves a new copy with "(annotated)" at the end of the name. The original file does not change.
Note: a PDF with a password does not open in the annotate screen. Remove the password with the Unlock tool first, then sign the unlocked copy.
How do you use the same signature again?
You draw your signature one time. PDFriend saves it in the private storage of the app on your phone. The next time, tap Signature, then tap the page where the signature must go. The app puts the saved signature at that point, and you do not draw again.
The app does not upload the signature. An uninstall of the app deletes it. If you turn on the Google backup of your phone, Android can copy the app data, with the saved signature, to your Google account.
Tip: if the signature is in the wrong place, drag it again before you save. To remove it, tap Undo.
How do you fill and sign a PDF form?
Many forms have fields: boxes for your name, check boxes and lists. Fill these fields with the Fill form tool. It writes the values into the fields, so they line up with the form. Then sign the filled copy.
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Open Fill form
Open the PDF form in the viewer, tap the menu (three dots), then tap Fill form. You can also tap More on the home screen, then tap Fill form.
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Fill the fields
The screen lists the fields in reading order. Each field shows the part of the page around it, so you see the question next to the field. Type the text, and tap the check boxes and the options.
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Save the filled copy
Tap Save as new PDF. The app saves "<name> (filled).pdf". The result screen shows the file.
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Sign the filled copy
Tap Open on the result screen. Then sign it with Annotate and sign, as in the steps above.
By default, the values become a part of the page, and every PDF app shows them. Turn on Keep the fields editable if the receiver must change a value later. Some apps do not show the values of editable fields.
Note: if the app says "This PDF has no form fields", the form is a flat page. Use Annotate and sign for the whole form: the Text tool for your name and the date, the Pen for a tick, and Signature for the signature.
What else can you add to a PDF?
The annotate screen has 5 tools. You can use them on every page of the PDF, and you can move between the pages.
| Tool | What it does | Typical use |
|---|---|---|
| Pen | Draws a line where your finger goes | Initials, a tick in a box, a circle around a word |
| Highlighter | Draws a line that you can see through | Mark an important sentence |
| Text | Puts a text box on the page | A date, your name, a short note |
| Signature | Puts your saved signature on the page | Sign a form or a contract |
| Whiteout | Covers a box on the page with white | Hide a wrong date, then write the correct one with Text |
The Pen, the Highlighter and the Text tool have 5 colors: black, red, blue, green and yellow. The Pen and the Highlighter have 3 widths: Thin, Medium and Thick. Undo removes the last change. Clear page removes all changes on the current page.
Important: Whiteout hides content only from the eye. The covered text stays in the file, and a PDF search or a copy still finds it. Do not use Whiteout to remove private data before you send a file.
The sign tool in numbers
These facts describe PDFriend 1.0.2 on Android 9 and later.
| Where | PDF viewer, menu, Annotate and sign |
|---|---|
| Tools | 5: Pen, Highlighter, Text, Signature, Whiteout |
| Colors and widths | 5 colors, 3 line widths |
| Signature type | A drawn image, saved on the phone for the next PDF |
| Output | A new file, "<name> (annotated).pdf". The original does not change. |
| Added text | Goes on the page as an image, so a PDF search does not find it |
| Form fields | Fill form: text fields, check boxes, radio buttons and lists. Not signature fields. |
| PDF with a password | Unlock it first |
Is a drawn signature legally valid?
A drawn signature is an image of your handwriting on the page. Many people use it for everyday forms, for example a school form or a delivery note. It shows that you signed, the same as ink on paper.
Important: a drawn signature is not a certified digital signature. It does not check your identity, and it does not lock the document against changes. For a legal e-signature with identity checks, use a certified e-signature service.
Ask the person who sent the document which type of signature they accept. The rules are different in each country and for each type of document. To send the signed file in a small size, read how to compress a PDF on Android.
How do you sign a PDF on iPhone?
PDFriend is also an iPhone app (iOS 26 and later). Open the PDF, then tap Annotate and sign and Signature. Draw your signature in the box and tap Save to keep it for later use. Put it on the line, then save the PDF. For a form with fields, use Fill form first. The PDF goes to the folder of the app. In the Files app, open On My iPhone > PDFriend.
Questions and answers
How do I sign a PDF on Android without printing it?
Open the PDF in PDFriend, tap the menu, then tap Annotate and sign. Tap Signature, tap the page, draw your signature and tap Save. Move the signature to the line, then save the PDF. You do not need a printer or a scanner.
Do I have to draw my signature every time?
No. PDFriend saves the signature on your phone after you draw it one time. The next time, tap Signature, then tap the page. The saved signature goes on the page at that point.
How do I sign a PDF form that has fields?
Fill the fields first with Fill form, then save the filled copy. Open the filled copy, tap Annotate and sign, and put your signature on the signature line. Fill form does not fill a signature field.
Is a drawn signature a legal electronic signature?
A drawn signature is an image of your signature on the page. It is not a certified digital signature, and it does not prove your identity. For a legal e-signature with identity checks, use a certified e-signature service.
Can I hide a wrong entry before I sign?
Yes, from the eye. The Whiteout tool covers a part of the page with white, and you can write new text on it. The covered text stays in the file, so a PDF search or a copy still finds it. Whiteout is not redaction.
Does the app upload my signature?
No. PDFriend keeps the signature in the private storage of the app on your phone, and an uninstall deletes it. If you turn on the Google backup of your phone, Android can copy the app data, with the signature, to your Google account.
Can I sign a PDF that has a password?
Not directly. Remove the password first with the Unlock tool. Then sign the unlocked copy.