as the title shown how to use present perfect>?
It has several uses, but as I said in answer to your other post, use it when a past event relates to the present time in some way:
I've lost my key. (at some time between the past and right now, and do not know how to get into my house)
I have never seen a purple cow. (from the past until now)
I have always eaten sushi on Sunday. (from the past until now and I intend to continue into the future)