How Do I Archive? Or Do I?

Can anyone tell me how archiving is accomplished in WordPress? Do I need to do anything? Does the number of categories create any conflicts when archiving? Is archiving enabled during the automated installation, or does it require a manual configuration?
I looked on Wiki, and on WordPress, but I could find any specific information on archiving. Not that it isn’t there, just that I couldn’t find it. So if someone could provide me with a link, or a summary brief, I would be very appreciative. Thank you.