Which sentence is correct?- All are good. Do I need to add "which" or " that" in the sentence?-- No. I am confused with the usage of present perfect and past tense. -- Here it makes no real difference. For the differences, read about them in our FAQs:
So do you mean I can mix the tense in one sentence? eg: I have bought the dress she liked. (present perfect + past simple) I bought the dress she likes. (past simple + present simple)