Ability for respondents to sign a document

Do you have the ability to have my clients sign a document after answering questionnaire? ? 

You can add a signature field in your form so your respondents can put in their signature and you form can be set up so that a PDF Document that includes their signature will be generated.

How-to-Add-an-E-Signature-to-Your-Form

How-to-Customize-PDF-Submissions-Report

Or, you may also try setting up a DocuSign widget or an AdobeSign widget in your form.

How-to-Add-a-Widget-to-your-Form