At this point I'd suggest doing some Googling to find out. That's what most of us end up doing anyway. I think we mentioned the Moonpig package; check plover.com for an interesting story about this Perl package that's used to build a billing system for an email service. (Fair warning: Mark-Jason Dominus, the proprietor of plover.com, will probably not be polite to you if he thinks you've not done your own research before you start asking him questions. Read his article on plover.com and take a look through the source on GitHub before asking him any detailed questions. If you ask him vague ones he may not bother to answer you at all.)
The new Built In Perl site may help you get a better idea of what Perl's being used for nowadays - but you really need to start finding this data yourself and putting it into your own words - this is the reason your instructor has asked you to look into this. Try doing some searches on the stuff you want to know - it's more work than having us just tell you, but this is a skill you need to develop to work effectively.
Computer programming is really about communicating with other humans using a language that happens to be executable. You need to learn to do that well before you can program well - bot listening, and writing/speaking yourself.
You can do this. Go for it!