The present perfectThe aspect expressing completion. E.g.: He’s finished university. tenseA grammatical category that is marked by verb inflection. To express when an event or action happens in time or when a state exists, we use tenses. is used for actionA general term expressing that somebody or something does somethings in the past if their exact times are not known or not important. The emphasisSpecial importance or attention given to something. E.g.: All I wanna do is have some fun. is on the fact that they happened before the time of speakingA point of time at which an utterance is made..

I've been to China.

Note that in such a sentence we use the preposition to instead of in. Also note that if we mention when this happened, we will have to use the past simple tense. In this case, however, the preposition in is used.

I was in China in March 1989.

We also use the past simple if we ask when something happened in the past.

"Have you ever been to China?"
"Yes, I have."
"When did you go there?"

Diagrams

Form: present perfect
Present perfect Present perfect for recent events with a result in the present