My statement was more for example than an actual statement of how hard drive manufacturers ship their products. The answer to your question really depends on the individual hard drive manufacturer. Sometimes hard drives need to be setup with the manufacturer's diagnostic utility prior to system installation and sometimes they do not since they are preset before shipping from the manufacturer.
But take a look at the core idea:
"Bare metal" hard drive -> create partitions -> format partition -> install operating system or store files
Formatting a partition means to install the filesystem so the operating system can communicate with the storage space available on the partition of the hard drive.
