HTC One AT&T Wi-Fi hotspot Mod
As expected, network provider AT&T has not enabled Wi-Fi hotspot functionality on the HTC One. There is a mod available that enables it and the best part is that it works with both rooted and non rooted HTC One phones. The only thing required is CWM recovery.
Make sure not to abuse this service as it might raise flags. I have been using it for years and have never been flagged.