You cannot autopopulate your signature. If that were possible, then it would be possible for someone else to place your signature on a document signing away your house. Not ideal.

Set yourself as the first recipient within your template/envelope with a signature tag in the correct location. When you finally send the envelope, you'll be offered the opportunity to sign the envelope immediately. Sign and thus place your signature before it is routed to the customer. Make sure your customer is at (https://support.docusign.com/en/guides/ndse-user-guide-signing-order) Signing Order 2 while, you're at Signing Order 1. That way the customer won't receive the envelope until you have added and completed your signature.

Hope this helps.