Enable/Set on-prem user as remote mailbox o365

Enable-RemoteMailbox -identity user -RemoteRoutingAddress user@xyz.mail.onmicrosoft.com

Enable-RemoteMailbox -identity user -Archive 

Bulk script -

foreach($i in get-content C:\New_folder\123.txt){Enable-RemoteMailbox -Identity $i@xyz.com -RemoteRoutingAddress $i@xyz.mail.onmicrosoft.com}

Get-Content "C:\New_folder\123.txt" | Enable-RemoteMailbox -Archive