Nprinting can use any custom email address as it only acts as an email client. If you would like to customize your sender address, I would contact your E-mail administrator team to request the creation of the smtp address that you would like to implement. (ex: nprinting@yourcompanyname.com)
Please don't forget to mark a correct resolution or answer to your problem or question as correct, as it will help other members to find solutions more easily 😉