Questions & Answers about पार्सल और लिफ़ाफ़ा काउंटर पर हैं।
Because the subject is compound: पार्सल और लिफ़ाफ़ा = the parcel and the envelope.
Even though each noun is singular by itself, together they make a plural subject, so Hindi uses हैं (are) rather than है (is).
- पार्सल ... है = The parcel is ...
- लिफ़ाफ़ा ... है = The envelope is ...
- पार्सल और लिफ़ाफ़ा ... हैं = The parcel and the envelope are ...
Hindi usually does not use articles like a, an, and the the way English does.
So पार्सल can mean a parcel or the parcel, and लिफ़ाफ़ा can mean an envelope or the envelope, depending on context.
That means the sentence can be understood as something like:
- The parcel and the envelope are on the counter
- or A parcel and an envelope are on the counter
The exact choice comes from the situation, not from separate article words.
Hindi uses postpositions, not prepositions.