Apple added support for the iCloud Shared Photo Library in the third version of the operating system, which was released to developers today.
It's possible to set up the iCloud shared photo library in the settings app after you've installed any of the above mentioned operating systems. Click on "Shared Library" to scroll down.
To add participants you want to share with, tap on "start setup" from there. You can invite up to five other people, and all of them have access to the library. If you don't have a Family Sharing setup, you can add anyone.
You can choose to move your photos to the shared library after you select people to share with. All of your photos and videos can be moved or you can choose photos manually.
You can preview the library before it's shared, and then officially invite participants using the Messages app or a shared link. Participants will have access to all photos uploaded to the shared library.
Smart setup rules can be used to prevent accidental sharing of photos. Photos from a specific start date can be shared. It is possible to share photos with only your family members.
There are options to share photos based on proximity in the shared library. Sharing suggestions will show up in For You too.
If you're on vacation with your family, you can use the Camera app to automatically uploaded all your photos to the shared library, so everyone can see them when they're snapped.
Similar to standard iCloud Library images, shared photos will show up in Memories, featured photos and the Photos Widget.