The present perfect simple is : have/has + past participle.
The past participle often ends in -ed ( finished / decided ..), but many important verbs are irregular (lost/done/been..)
When we use the present perfect there is always a connection with now . The action in the past has a result now :
' Where's you key ? ' ' I don't know . I've lost it ' ( I haven't got it now. )
He told me his name but I've forgotten it .( I can't remember it now. )
We often use the present perfect simple to give new information or to announce a recent happening :
Ow! I've cut my finger.
The road is closed. There has been an accident .