There — a place relatively near the listener. Used to indicate a location close to the person you're speaking to (e.g., "put it there").
その箱をそこに置いてください。
Please put that box there (near you).
そこ、立たないで。危ないよ。
Don't stand there. It's dangerous.
鍵はそこにありますよ。
The key is there (by you).
There — referring to a place just mentioned; that place previously referred to.
昨日行った店、そこは料理が美味しかった。
The shop we went to yesterday — that place had good food.
資料は机の上にある。そこを確認しておいて。
The documents are on the desk. Check that place.
There/that — referring to a fact or point just mentioned; used to mean 'that (point)' or 'then' in the context of the preceding statement.
彼が遅刻した。そこが一番の問題だ。
He was late. That's the main problem.
給料が下がった。そこを改善しないと辞める人が増えるだろう。
Salaries were cut. If that isn't fixed, more people will quit.
An archaic usage where そこ can function like a second-person pronoun ('you'); rarely used in modern Japanese and mainly seen in classical texts or old plays.
古い芝居の台本で『そこ、出でよ』という台詞が残っている。
In an old play script there's a line like 'There, come out' (archaic use).