These three words sound alike but have different meanings.
There usually refers to a place or introduces something.
- Put the bag over there.
- There is a problem.
- I have been there before.
Their shows possession.
- They brought their children.
- The students opened their books.
- The company changed their policy.
They’re means they are.
- They’re coming soon.
- I think they’re ready.
- They’re very happy.
Easy way to remember
There = place
Their = belonging to them
They’re = they are