public/Get-Abbreviaion.ps1

function Get-Abbreviation {
    <#
    .SYNOPSIS
        Get abbreviation from string of words
    .DESCRIPTION
        Derive an abbreviation from a string of words
    .PARAMETER String
        Required. Input string value.
    .EXAMPLE
        Get-Abbreviation "Eastern Standard Time"
         
        Returns "EST"
    .LINK
        https://github.com/Skatterbrainz/helium/blob/master/docs/Get-Abbreviation.md
    #>

    param (
        [parameter(Mandatory)][ValidateNotNullOrEmpty()][string]$String
    )
    $($String -split " " | Foreach-Object {$_.Substring(0,1).ToUpper()}) -join ""
}