You can set it up so that the account is generated automatically, but this is usually a bad choice on the part of the reseller. Why? Because this makes them a target for fraud and the like, as they do not do any credit card authentication, or any real authentication for that matter.
However, this is just for the generic reseller. I'm sure there are some large hosting companies that have automated the process by now, but it is probably with internal software.
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There are some scripts that can automate account creation but I've never used any. I think ModernBill does it but you need root access to set up and install. Therefore it's not built for resellers.
Pretty sure the same is true of Cpanel. WHMautopilot etc needs root access to setup and install, I believe. Might be wrong as auto account creation is something I'm not a fan of and haven't bothered to fully research.
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