Automatically Backup All of Your Photos
Your iPhone 8 can automatically back up all of your photos to iCloud or to Google Photos so that you never have to worry about losing pictures if you break your phone or if it is lost.
iCloud Photo Library will keep all of your photos online so you can see them all at any time, but you may need to buy more iCloud storage to fit them all. Go to Settings -> Tap on your name at the top -> iCloud -> Photos -> On.
With Google Photos, you can also backup all of your photos to Google for free at a lower resolution, or pay for storage to back them up at full resolution. Download Google Photos to get started.
Both options also back up videos and in many cases will keep your photos online without keeping all of them on your phone. If you have an internet connection you can see all of your photos, but if you are offline you may only be able to see a few.