If you need to verify files are untampered with, you have to create a file checksum -or file hash- that you can use to verify. PowerShell offers this functionality with Get-FileHash cmdlet. Or use certutil.exe.
In this post I provide you with a small PowerShell function you can use to send email over a TLS secured SMTP connection with SMTP authentication. As a framework you can use in your own scripting and extend it. You can even create a PowerShell module of it.