SMS and WhatsApp Delivery Notifications
fmESignature Link v2 includes support for sending requests with SMS and WhatsApp Delivery. SMS and WhatsApp Delivery allows you to notify signers via SMS in addition to the standard email notification. SMS and and WhatsApp notification messages are in addition to email notifications.
DocuSign Account Setup
To use SMS and WhatsApp Delivery you will need to enable this feature in your DocuSign Account Sending Settings by checking the Allow SMS delivery to recipients checkbox:

Contact DocuSign Sales to check if this feature is available for your account and to have it enabled.
Contacts Setup
To send an SMS or WhatsApp Notification to a Signer or Carbon Copy recipient you will need the following information for each Contact recipient:

Mobile: enter the mobile number of the recipient without any + characters or country codes etc
Country: select the Country for the recipient from the drop down list. We use this to match to the Countries table to get the correct Country Code for the recipient's country.
Request Setup
On the Request Recipients tab click this popover button:

to view the SMS/WhatsApp Settings:

You can select either SMS or WhatsApp from the SMS/WhatsApp drop down menu. The total number of SMS delivery recipients is limited to 10 - please familiarise yourself with the rules and limitations around SMS delivery notifications first.
When you send your request any recipients with the SMS or WhatsApp option selected, in addition to the standard email notification, receive an SMS notification on their mobile phone:

Signers who receive SMS or WhatsApp notifications are more than likely to sign the document using a mobile device, so it is recommended that you turn on Responsive Signing and test your documents with mobile devices first to ensure they work correctly. With Responsive Signing signers will see a mobile optimised view of the document (you can toggle between the standard PDF view and the mobile view using the Mobile-Friendly toggle at the top of the screen):

Once the document has been signed by all recipients another SMS or WhatsApp Notification will be sent with a link to download the completed document in addition to the standard email notification:

You can get more information on SMS Delivery at the following links:
Introducing eSignature SMS Delivery: A Faster Way to Reach Signers
Multi-Channel Delivery for Notifications: SMS and WhatsApp
Docusign SMS and WhatsApp Service
eSignature REST API SMS and WhatsApp delivery
SMS Delivery with the eSignature REST API