https://sign.dropbox.com/en-GB/resources/implementing-sms-signer-authentication-with-the-twilio-api
Implementing SMS Signer Authentication With Twilio API - Dropbox Sign
Watch as we discuss the new feature, why we used Twilio to guide the build process and how you can implement your own Dropbox Sign document signing workflow...
signer authenticationimplementingsmstwilioapi
https://help.dropbox.com/security/dropbox-sign-signer-authentication
Add signer authentication to signature requests - Dropbox Help
Learn how to add signer authentication in Dropbox Sign using SMS codes or passwords to ensure the right person signs your document.
signer authenticationsignature requestsadddropboxhelp