Technically any envelope you create, the Recipients are only notified via email. However if you create a Template and then turn it into a Powerform you could text that link to the Powerform to the customer/recipient. It is obviously an extra manual step.

I have seen several Community posts requesting a feature for text notifications and I think it is a valid enhancement request with how people use their phones now more than email so I would suggest sending in feedback to DocuSign.

Eve​n though it has been over 2 years from this post, has there been any updates? Is there a process where a customer can just answer a couple questions on their cell phone then it is directed to an approval page?

Please advise

With a more recent release I believe December, DocuSign introduced SMS messaging, as seen in the message via an email from DocuSign...I checked in with my Acct Manager and this is an additional charge if enabled on your Account, so I suggest contacting your Account Manager to enable and understand the charges.

SMS Delivery for eSignature

Want to notify your signers via SMS? With SMS Delivery, you can now send real-time text notifications directly to a signer’s mobile device, helping ensure signers receive and complete important documents quickly.

Available as an add-on to eSignature Standard and above plans. For more info, click here.