how can i copy all of my photos from iphone to pc ?

it is very easy ,

1. Make sure that you have the latest version of iTunes on your PC. Importing photos to your PC requires iTunes 12.5.1 or later.
2. Connect your iPhone, iPad, or iPod touch to your PC with a USB cable.
3. If asked, unlock your iOS or iPadOS device using your passcode.
4. If you see a prompt on your iOS or iPadOS device asking you to Trust This Computer, tap Trust or Allow to continue.

You can also check this Link https://support.apple.com/en-us/HT201302

Follow the steps here:

https://support.apple.com/en-us/HT201302