To get the current user selected shipping address in shipping method use RateRequest Object request in collectRates method as,
Country Id -> $request->getDestCountryId() Region Id -> $request->getDestRegionId() Region code(String) -> $request->getDestRegionCode() Zipcode (Postal) -> $request->getDestPostcode() City -> $request->getDestCity() Street -> $request->getDestStreet() All quote items -> $request->getAllItems()
Country Id -> $request->getDestCountryId()
Region Id -> $request->getDestRegionId()
Region code(String) -> $request->getDestRegionCode()
Zipcode (Postal) -> $request->getDestPostcode()
City -> $request->getDestCity()
Street -> $request->getDestStreet()
All quote items -> $request->getAllItems()