"over" emphasizes distance or difference. "Doing something like that might be OK in your country, but over here it's completely unacceptable." By adding the "over", I am emphasizing that my country is different from yours. "Please put the box right there."=The box needs to go in the exact spot I'm pointing to. "Please put the box over there."= I don't want the box near me, but you can put it anywhere in the general region I'm pointing to. "Come here for a second" and "come over here or a second" are almost exactly the same, but adding "over" makes it sound like the person needs to walk farther to get there, or stop doing what they were doing before, or move from one room to another.

"Over here and over there" often indicate the location of an object, person, thing, the only difference between these two is that "over here" means the object, person, thing is closer. "over there" means the object, person, thing is further!

Thank you Joy! :)

“Over” when used as a preposition is used to address sides, which could be sides of a room, street, town, country or even a table. For example “ I will sit here and Natasha you sit over there” or “My car is parked over there as there was no space over here”. “Here in London it is sunny but over in Liverpool it is raining”. In my examples THERE is used as an adverb as we are talking about places and positions.