imported photos from iphone have the wrong date. How to fix???

Hi azpix,  I assume you have all the photos on the wrong date/time.  If so, go to the Library or Grid view mode (hit "E" or "G" on your keyboard). Select all the photos you know have the wrong date/time and go to the top to the tab "Metadata" and find "Edit Capture Time".

Here you can easily change the date/time.  I usually take option 1 "Adjust to a specified date and time".  It will adjust the picture date/time from the one displayed, all others will be changed accordingly (meaning if image 2 was captured 1 hour later, it will change that image to the specified date/time +1 hour).  Hit change.  You will get a message that this operation can't be undone, hit OK - I have rolled back the time successfully in the past, should you have missed the date somehow.

I generally use the option to synchronise mutliple cameras during event shooting.