Isim means noun such as house بيت or room غرفة or table طاولة
Examples of har jar حرف جر are as follows:
من، على ، فى
Translation is “from”, “on top”, “in” respectively.
Noun followed by حرف جر has a “ei” sound at the end.
In the house. فى البيتِ
From the room. من الغرفةِ
On the table. على الطاولةِ
In the above sentences all the nouns such as بيت ، غرفة، طاولة are مجرور meaning they have “ei” ending sound.
There are many examples in the Quran such as in surah naas we have