All of the valid email aliases for a user appear here and can be edited. When you edit, you have the opportunity to set a different address as the default. If you do, the different address will have SMTP type in capital and bold letters; this indicates the default address. The SIP address (usually, but not always—the same as the SMTP address) is the one used by Skype for Business and the SPO address (generally an obscure-looking GUID) is used by SharePoint Online:
Editing mailbox: email address
We already mentioned how to use PowerShell to append a new email address, but what if you want to use PowerShell to set multiple ...
