The present perfect uses “have” or “has” to describe an action completed before now, as in “I have eaten.” It combines the present-tense auxiliary have or has with the past participle of the main verb: “have finished,” “has arrived,” or “have seen.”
It is called “present” because the auxiliary is in the present tense, and “perfect” because the action is viewed as complete relative to the present. The tense often emphasizes a current result or experience rather than the exact past time: “She has lost her keys” suggests that the keys are still missing.
A common mix-up is the simple past, which normally refers to a completed event at a definite past time: “I ate breakfast at eight.” The present perfect generally avoids a finished-time expression such as “yesterday.” It can also describe situations continuing to now, as in “I have lived here for five years,” so completion is not its only possible meaning.