$f = 'c:\xampp\htdocs\Health_link\index.php'
$t = [IO.File]::ReadAllText($f)
$old = "Women''s health, urine screening, and workplace programmes as private home kits, with results synced to your app."
$new = "Women&#39;s health, urine screening, and workplace programmes as private home kits, with results synced to your app."
$t = $t.Replace($old, $new)
[IO.File]::WriteAllText($f, $t)
Write-Host 'Done'
