Here is a list of Exchange Online Powershell commands that I have had to research to fix some somewhat obscure issues.

Connect to Exchange Online with MFA

Connect-ExchangeOnline -UserPrincipalName useraccount@domain.com -ShowProgress $true

Add email alias to Office365 Group

Get-UnifiedGroup #Returns the List of all groups in Office365

Set-UnifiedGroup -Identity GroupName -EmailAddresses @{Add="newalias@newdomain.com"}