The difference between the two is very interesting, and the complex number of the next order is different. Usage depends on whether singular nouns or plural nouns are added.

1 has a different meaning: there is something somewhere, and there is often only one thing behind it. There also means that there is something somewhere, often followed by a pile or group of things.

The plural of the next order is different: there is a singular subject, and the be verb uses. There is a subject in the plural, and the be verb uses are.

The usage of 3.there is to add singular nouns or uncountable nouns. The usage of the is to add plural nouns directly.