Everything is done manually. I personally don't do it though.
I don't like using scripts such as ModernBill and WHMAutoPilot to automatically create the hosting account and so on. Yes, it can save time - however I just prefer it if I have my employees do it.
Currently I don't use an online billing system, however do plan to in the future, yet don't think I'll ever have accounts created automatically. I've employees who are more than willing to do it, and also as said already, it can create better relations with clients.
The clients shouldn't be cross, or annoyed that the account has taken some time to be created. At least then they're guaranteed (or hopefully should be) that it was done correctly. All accounts are created, by my employees, within twelve to twenty-four hours; I don't think it's too long as sometimes employees have to call up the clients and confirm things. Also at times clients wish to have things specially done to their accounts (such as having a script installed), which means more time is taken to create the account and actually make sure that the script which has been installed is working perfectly without problems (
There's no point installing a script, yet it doesn't work!).
If I were the client, I personally wouldn't mind waiting twenty-four hours to have my account setup - true, it's a whole day (twelve hour day & twelve hour night), but as long as everything is setup as I requested, I wouldn't have a problem at all.