As per this article https://support.apple.com/en-in/HT201060
When you set up your family, a shared album is created automatically in the Photos app on all family members’ devices. Everyone can add photos, videos, and comments to the album whenever they like and get notified when something new is added.
You can't view photos of shared family photos on www.icloud.com , perhaps can view them on all devices , for that you need to need to leave family sharing https://support.apple.com/en-in/HT201081
And then sync the apple devices by signing in with same Apple ID and password on the same high speed network and the photos will sync see this article https://support.apple.com/en-in/HT204264
See this article also https://support.apple.com/en-in/guide/photos/pht1324a500e/mac
https://support.apple.com/kb/ph12068?locale=en_US
If you turn on the Public Website option in your shared album settings, anyone can view your album on the web, even if they don’t have Shared Albums set up.