i am using PayPal Checkout Add-On which works great.
how is it possible to get the user email and street/postcode/city from the paypal?
the goal is that the user does not to fill this fields or better there are hidden, but populated.
Populating fields with values from PayPal is not a feature of the add-on. You can suggest this feature directly to the product management team, for consideration when planning future releases, on the Gravity Forms product roadmap page.