How to Sign a PDF on iPhone, Android, Mac, or Windows
No matter which device you use, whether it’s iPhone, Android, Mac, or Windows, signing a PDF should be simple, fast, and secure. With a modern e signature platform like SignBox, you can sign documents online in minutes without downloading apps or installing software.
Whether you’re closing a deal, approving a contract, or reviewing an NDA, the process is the same across all devices: upload → sign → download.
Why Signing PDFs Digitally Works on Any Device
Digital signing removes the limitations of device type or operating system.
When you sign a PDF online, you get:
- Consistent signing experience on all devices
- No printing or scanning
- Faster agreements
- Secure and organized file management
- Instant access from your browser
Whether you’re on the go with a phone or working from your computer, digital signing keeps everything simple.
How to Sign a PDF with SignBox on Any Device
You can sign a PDF using SignBox from iPhone, Android, Mac, or Windows. The steps are identical because everything works directly in your browser.
Step-by-Step
- Open SignBox in your browser.
- Click Upload Document and select your PDF.
- Choose My Signature to create your e-signature
– draw, type, or upload your handwritten signature. - Place your signature where needed on the PDF.
- Download the signed PDF or store it securely in SignBox Drive.
No app installation is required, just a device with a browser.
Try SignBox now for Free →
Device-Specific Notes
iPhone & Android
- Works from Safari, Chrome, or any mobile browser
- Perfect for signing documents on the go
- Receive signature invitations instantly via email
- Tap to sign in seconds
Mac & Windows
- Works on Chrome, Safari, Firefox, and Edge
- Drag-and-drop upload for your PDFs
- Easy to sign agreements, proposals, NDAs, or invoices
- Ideal for professionals managing multiple documents
No matter the device, every signature is linked to a unique signer ID, helping verify identity and prevent fraud.
Do I need to install an app to sign a PDF?
No, you can sign directly from your browser on any device.
Can I send PDFs for others to sign?
Yes. Invite signers by email, even if they use different devices.
Do signers need an account?
Yes, they confirm their email and sign in to verify identity.
Is signing a PDF secure?
Yes. SignBox stores your signed PDFs securely and links each signature to a unique signer ID.
Sign PDFs Easily from Any Device
Upload → Sign → Download.
Fast, secure, and compatible with iPhone, Android, Mac, and Windows.
Sign your PDFs the smart way with SignBox.
Can I Use e-Signatures for Legal or Real Estate Documents?
Yes, in many cases, you can use your e-signature to sign legal or real estate documents. For most agreements, contracts, NDAs, proposals, lease negotiations, and property transaction forms, signing documents online is accepted as long as both parties agree to sign...
How Can I Sign NDAs, Invoices, or Proposals Digitally?
Signing NDAs, invoices, or proposals manually (printing, scanning, emailing) wastes time and creates unnecessary friction. Using a digital signing workflow saves time, reduces errors, and improves the professional impression you leave. With the right signing platform,...
What’s the fastest way to collect signatures from a team or clients?
When multiple people need to sign a document, waiting for each person to print, sign, scan, and send it back slows everything down. The fastest way to collect signatures is to use an online signing platform that allows everyone to sign digitally from any device. This...