Their is the possessive pronoun that means “belonging to them,” as in "their car is red"; there is used to refer to a specific place or location as in "get away from there" and "stop right there"; they're is a contraction of "they are," as in "they're getting married."

There is and there’s are both singular forms. We use there’s more commonly in informal speaking: There is a new cafe in the centre of town which sells Indonesian food. She’s very determined and there’s no chance she will change her mind. There are is the plural form of there is and there’s: There are two new buildings next to the school.

There is an adverb which refers to places: The shop you need is over there. We also use there to say that something exists: There is a large oak tree outside the hotel. Their is a possessive determiner which means ‘belonging to them’: Their house is very small, isn’t it? They’re is a shortened form of ‘they are’:

There can act as several parts of speech: as an adverb, adjective, pronoun, or noun. In general, you can think of there as typically referring to a place or point in some way, but it can also be used interjectionally or for emphasis.