Hi @Svetlana !
Sorry if I didn't understand your question correctly, but would you like to know more details about the additional security verification for your recipients or would it be about the Two-Step Verification that users of your account can use to access Docusign (to manage envelopes)?
If you are referring to SMS authentication of your recipients, I recommend you to watch this video belowand check the following article: How Phone Authentication Works
However, if you want to know more about the Two-Step Verification that will affect how your users will log in to the platform, I recommend you read this article below: Set Up Two-Step Verification With Text or Call
Please, let me know if I was able to help you with this question. If so, could you please select click on the "Select as Best" option? Thank you!