Provisioning time depends on the product type, stock, and any setup steps required before the service is ready. Many server orders are prepared quickly, but the exact timing can vary based on the service you purchased.
You should treat the activation and welcome information in your account as the final confirmation that the server is ready to use. Do not assume the service is live until you receive the access details or see the active status in the client area.
If you have a time-sensitive deployment, build in a little buffer instead of planning against the shortest possible turnaround.