HTC Backup can be found in Sense 5.0 and up. This is from a One with 4.3/Sense 5.5
Set it up by going to Settings > Backup & Reset, where you under Backup Account select the type of backup you want. In our case we select HTC account, as I’ve already setup my account I don’t get any questions about Dropbox or so. If you do, just ok those.
If you want to select storage service, you got to Menu > Select Storage Service. There you can select Google Drive or Dropbox.
When all things setup you can simply click Backup now or have it set to Automatic Backup where it will backup daily.
If you want to read more about the entire process around when you factory reset a phone, read this.