The are several ways when we want to use the present perfect tense
1.It is to expres an action that happened at an indefinate time on thw past.
-Ramli has traveled around the world.(we dont know.wen)
-I.have al ready enten lunch
-have you done tuw job
2.It is expres an action that happened more than once in the past.
-sirajan has seen those movies three time each.
-they have visited the square twice.
-we have had drink in that cafe many times.
3.The present perfect tenae is to express an actiom in the past and still occuring in the present.
-Anna and I have been in the class since ten o'clock this morning.
-Ghazi has lived in the same house for twenty years(he still lives there.)
-Ghazi has liven in the same house since 1975.