i want to export photos from my windows pc to my iphone

There are multiple ways to do this.

You can use iCloud for Windows and push your photos to iCloud. https://support.apple.com/en-ca/HT205323

Or you can use iTunes to perform a sync of your photos. https://support.apple.com/en-ca/guide/itunes/itns3102/windows

If you want a more comprehensive guide on both options and their differences, look here: https://support.apple.com/en-ca/HT201313.

Please let me know if you have any additional questions.