Hi,
While each user can specify their own local address, there is one Account Address associated with the DocuSign account which is generally the billing address associated with your license. This is the address that gets recorded on the Certificate of Completion rather than the address associated with the Sender's user record. There is no mechanism for changing what gets written to the CoC. If you feel strongly about this, you can work with your Account Manager to request a product enhancement.
Regards,