Time line showing the use of Present Perfect Tense
We use Present Perfect to talk about action/state/habit that started in the past and continues to the Present.
I have liked chocolate since I was a child.
She has had this cat for three years.
SINCE AND FOR
‘SINCE‘ is used for ‘fixed time in the past’. (2007. last month, or another past action)
She has been at work since 8 a.m.
‘FOR‘ is used for ‘a period of time’. (3 hours, 6 years, seven months, a long time, etc.)
He has been at work for 12 hours.
I have been busy for 3 hours.
Present Perfect is used for an action which has recently finished but the result is visible/felt now.