If you have made the payment online using credit card or PayPal, your domain names, in most cases, are registsred instantly and hosting account is also setup instantly. You should receive email within minutes.
In some cases, auto-setup is not possible and it that case, accounts are setup manually as early as possible after we receive the payment. Account login information with username and password are emailed not later than 24 hours after the receipt of your payment.
For dedicated servers, it may take a little longer to complete the setup and install Operating System for you.