here are some examples from a grammar book :
you can use the present perfect for new information:
- "I've decided to quit my job." "Really? Why?"
- We've sold our car. Now we take the bus every day.
- They're having a party next week, but they haven't invited me.
- I'm looking for Amy. Have you seen her?
you can also use the past in these examples:
- I decided to quit my job
why just example 1 can be written in past form? and actually, by this fact it should not!
Present Perfect. This tense describes something that happened in the past, but that is related to something in the present.
in general when we can use simple past instead of present perfect or vice versa?