How to Require SMS Two-Factor Authentication for PDF Signatures
Question details
A business needs to require document recipients to authenticate their identity using an SMS text message PIN before they can electronically sign a PDF.
- Product
- Adobe Acrobat Sign
- Device & OS
- not provided
- Scenario
- Sending sensitive business documents for electronic signature where high-security signer verification is necessary.
- Observed behavior
- Senders need the correct workflow to enforce recipient mobile authentication instead of relying on standard email links or Adobe account logins.
Verify that your electronic signature service plan includes advanced authentication features and ensure you have the correct mobile phone numbers for all recipients.
Configure SMS Authentication in Agreement Settings
Set up two-factor authentication via text message when creating a new document agreement to ensure only verified users can sign.
By enforcing SMS authentication, the recipient must enter a one-time password (OTP) sent to their mobile device before viewing or signing the document. This adds a critical layer of security for sensitive business agreements.
Log into your document signing platform (such as Adobe Acrobat Sign) and navigate to the 'Send' or 'Request Signatures' tab to start a new workflow.
Add the recipient's email address in the designated signer field.
Click on the 'Authentication' dropdown menu (often represented by a key or gear icon) next to the recipient's email and select 'SMS' or 'Phone'.
Enter the recipient's mobile phone number, ensuring you include the correct country code so the text message routes properly.
Upload your PDF document, place the required signature fields, and click 'Send'. The recipient will now receive a PIN via text message when they attempt to open the document link.
Sign and Secure PDFs Easily with WPS Office
If you need a reliable way to sign and secure your business documents, WPS Office offers powerful built-in PDF tools. You can add electronic signatures and apply strong password encryption to ensure your files remain completely confidential.
- 1. Open your PDF: Launch WPS Office and open the PDF document you need to sign or secure.
- 2. Add an electronic signature: Navigate to the 'Insert' or 'Protect' tab and select 'PDF Signature' to create and apply your personal or business signature.
- 3. Encrypt the document: Go to the 'Protect' tab and click 'Encrypt'. Set a strong password so only authorized recipients can open and view the file.
- 4. Share securely: Save the secured PDF and send it to your recipient, sharing the document password with them via a secure secondary channel like an SMS message.
Frequently Asked Questions
Why is the SMS authentication option missing in my account?
The SMS authentication feature may not be included in your current subscription tier, or your account administrator has restricted it. Check with your IT department or upgrade your service plan to access premium authentication methods.
Do signers need an account to use SMS authentication?
No. The text message PIN is sent directly to the mobile phone number provided by the sender. The signer simply clicks the document link in their email and enters the PIN; no account creation is required.
Can I use a landline number for SMS authentication?
No, SMS two-factor authentication strictly requires a mobile phone capable of receiving standard text messages. If the recipient only has a landline, you may need to use voice-based authentication if your platform supports it.
What happens if the signer enters the wrong SMS PIN?
If the recipient enters an incorrect PIN multiple times, the document link will typically be locked for security purposes. The sender will receive a notification and must resend the agreement or reset the authentication process.
