Turn on Shared Albums in Photos on Mac
To create albums you can share with others, you first turn on Shared Albums. You can also use Family Sharing to share photos with family members. See Set up Family Sharing.
Note: You can use Shared Albums only with your System Photo Library.
In the Photos app on your Mac, choose Photos > Preferences, then click iCloud.
Select the Shared Albums checkbox.
To turn off Shared Albums, deselect the checkbox. Even if you turn off Shared Albums on your Mac, you can continue to view and make changes to your shared albums using your other devices that have Shared Albums turned on.