Sender's name contains operator's "visible name" and "app name".
"Visible name" is also added to the email address.
"Visible name"= Myname
"App name"= www.mycompany.com
Sender's name: Myname www.mycompany.com
Sender's address: firstname.lastname@example.org (or your domain)
"Visible name" can be changed in Settings - Administrators.
Or you can also change personal data by clicking on operator's profile picture:
"App name" can be changed in Settings tab.