Credit agencies can 100% know when you pay you rent as the receiver can send this information to them. Credit cards also say when you pay so they can keep track of when you're delinquent or late for payments.
Credit agencies - at least in the US - really don't know when you pay the rent, though, unless the landlord reports this. Same for payments: This is a big part of the reason you cannot simply live within your means [1] and have good credit later in life.
You won't.
Many companies - utilities, landlords, hospitals, and so on - simply won't report anything unless it is negative. The negatives are usually sending something to in-house collections, a collection agency, or filing a civil suit to get the money.
Loans, in general, will report. This includes credit cards. Some of the buy here/pay here places won't report, though, so you get no help on your credit.
[1] What I mean by "live within your means" is to simply do things like pay cash for a used car, rent an affordable place, and simply pay your bills on time.
I think the person you are replying to is surprised that a landlord would bother reporting that information to a credit agency. I have never heard of that, and after using some of the bigger name property management companies in my area as both a renter and landlord, it just isn't normal here.
