Usage
To talk about things which happened in the past, and continue to the presentMy parents have lived in England for 20 years.
To talk about things which happened in the past, but not at a specific time
My mom has gone to work.
To talk about things we have done many times in the past and continue to do
She has practiced the piano since she was 6.
She has practiced the piano since she was 6.
This is the most beautiful flower I have ever seen.