how do i transfer photos to iCloud
Manage storage issue
how do I make more space with photos and transfer to shared iCloud
Turn on iCloud Photos to sync photos to iCloud; and also turn on the Optimize iPhone Storage option of iCloud Photos to potentially reduce the storage space needed on the device. See the following for more information on both: Set up and use iCloud Photos - Apple Support
Also note that Apple does not currently offer cloud-only storage for photos. If that is what you want or need, you may want to explore 3rd party options such as Google Photos or Dropbox.