Change from Write-Host => export to .txt or .csv

I have a script that currently runs great with results displayed in a console. I've been trying to figure out how to change the output to a file (.txt or .csv). I have created empty files and errors but no luck. I've had very limited experience so a suitable skill level solution/approach would be appreciated.

Can someone help me out?

Here is what I've got:

function CountMembers([string]$OU)

{ 

  $dom = [System.DirectoryServices.ActiveDirectory.Domain]::GetCurrentDomain() 

  $root = $dom.GetDirectoryEntry() 

  $search = [System.DirectoryServices.DirectorySearcher]$root 

## 

    $search.Filter = "(OU=$OU)" 

    $result = $search.FindAll() 

    $path = [ADSI]$result[0].path 

    $children = $path.psbase.children 

    $count = 0

##

        foreach($child in $children)

        {  

            if($child.objectcategory -like '*organizational*')

            { 

              CountMembers($child.name)

            } 

              elseif($child.objectcategory -like '*computer*')

                { 

                  [int]$count = $count + 1    

                }

        }          

         if ($count -gt 0)

        { 

            Write-Host "$OU | $count"

        }

}