$ExchParams = @{
    From = "my.sender.address@domain.com"
    To = "my.target.address@domain.com"
    SmtpServer = "ExchServToUseForRelay"

    Subject = "This is my subject."

    BodyAsHTML = "This is what will show up in the body of the message.<br><br>HTML can be used."

    Attachments = "C:\MyLocation\MyFile.ext", "C:\MyLocation2\MyFile2.ext"

    Encoding = "UTF8"

}


$GmailParams = @{
    From = 'you@gmail.com'
    To = 'someone@somewhere.com'

    SmtpServer = 'smtp.gmail.com'
    Port = 587
    UseSsl = $true

    Subject = "This is my subject."

    BodyAsHTML = "This is what will show up in the body of the message.<br><br>HTML can be used."

    Attachments = "C:\MyLocation\MyFile.ext"

    Encoding = "UTF8"
}

#sending via Exchange
Send-MailMessage @ExchParams -Credential (Get-Credential)

#sending via Gmail
Send-MailMessage @GmailParams -Credential (Get-Credential)

Podstawianie credentiali oczywiście też można zautomatyzować, np. poprzez eksport credentiali do pliku clixml i zaciąganie odpowiedniego pliku z zaszyfrowanymi danymi.