Use the Move to iOS app during iPhone setup
Turn on Google Photos on Android and sign in on iPhone
Upload photos from Android to Google Photos
Download Google Photos on iPhone and access the pictures
Use a computer to copy photos from Android to the computer
Connect the iPhone to the computer and import the photos with iTunes, Finder, or Photos
Use a cloud service like Dropbox, OneDrive, or Google Drive
Upload photos from Android to the cloud service
Download the cloud service app on iPhone and save the photos
Send photos from Android to iPhone through email or messaging apps for small batches
Use a USB transfer app or file-sharing app that supports both devices