Hi @Michael Shparber ,
May I ask where the recipient is viewing your mail address?
According to my research, you could change the display name of your account for improved readability.
Alternatively, you could edit the UPN addresses for the Office 365 user by using Azure Active Directory Module for Windows PowerShell. However, the address displayed to the recipient still appears to be lowercase after the change.
1.Import Azure Active Directory Module for your PowerShell:
import-module MSOnline
2.Connect to Office 365 by running this cmdlet:
$msolcred = get-credential
connect-msolservice -credential $msolcred
3.Change the UPN of your user:
Set-MsolUserPrincipalName -UserPrincipalName <current UPN> -NewUserPrincipalName <new UPN>
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