There are several ways:
Write-Host: Write directly to the console, not included in function/cmdlet output. Allows foreground and background colour to be set.
Write-Debug: Write directly to the console, if $DebugPreference set to Continue or Stop.
Write-Verbose: Write directly to the console, if $VerbosePreference set to Continue or Stop.
The latter is intended for extra optional information, Write-Debug for debugging (so would seem to fit in this case).
Powershell has an alias mapping for command echo to Write-Output, so:
$txtfilepath= "c:\test\test.txt" $txtfilepathSize = (Get-Item $txtfilepath).length; echo "txtfilepathSize : $txtfilepathSize"