Working with multiple rows from SQL

Maybe you could put a foreach loop on the results variable. You would need to modify the downstream variable names.

Foreach($Result in $Results){
    Rest of script using $Result for each SQL row
}

You're assuming your array is only returning one item. In general this is often a bad idea and I would explicitly force it into one @() at the time it's put into that variable. You need a for loop around your assignments from $result

That funky indentation was making my eye twitch, so I took some formatting liberties, but see if this might work.

$logfile = 'C:ScriptsLogslogs.txt'
Start-Transcript -path $LogFile -append
sleep -s 5

$query = @"
SELECT
    dbo.issues.IssueNbr,
    dbo.issues.IssueDescription,
    dbo.issues.SubmittedBy,
    dbo.issues.SubmittedDate,
    dbo.issues.AssignedTo,
    dbo.issues.TargetDate,
    dbo.issues.RequiredByDate,
    dbo.attachments.FileName
FROM
    dbo.Issues
INNER JOIN
    dbo.Attachments on dbo.Issues.IssueNbr = dbo.Attachments.IssueNbr
WHERE
    SubmittedDate < GetDate() and SubmittedDate > dateadd(minute, -5, GetDate()) and dbo.Attachments.FileName like '%.wav%'
"@

$results = invoke-sqlcmd -ServerInstance Server -Database Helpdesk -Query $query

Function Process-Result($result) {
    $issuenbr = $result.Issuenbr
    $description = $result.issuedescription
    $submittedby = $result.submittedby
    $submitteddate = $result.submitteddate
    $assignedto = $result.assignedto
    $filename = $result.filename



    If($assignedto -eq 'ittechs'){
        $toaddress = '[email protected]'
    }
    Else {
        $toaddress = Get-ADuser -identity bh3075 -Properties mail | Select-Object -ExpandProperty mail -ErrorAction Stop
    }

    $filepath = '\server$inetpubwwwrootAttachments'
    $attachmentname = $filename
    $file = ($filepath+$attachmentname)

    $MailMessage = @{
        To = $toaddress
        Bcc = "mecompany.com"
        From = "[email protected]"
        Subject = "issue $issuenbr $description"
        Body = "Greetings,<br><br>A ticket has been opened with a voicemail message. The voicemail is attached to this email<br> Issue Number is $issuenbr"
        BodyAsHtml = $true
        SmtpServer = "10.69.66.99"
        Attachments = $file
    }

    Send-MailMessage @MailMessage
}

If($results){
    ForEach($result in $results){
        Process-Result -result $result
    }
}
Else{<# Enter desired error handling when $results is $null #>}

Stop-Transcript

Edit: Remembered to adjust $results to $result inside the function.

Edit2: Added error handling section if $results array is null.