There are two ways to do this. Let’s take a look at both.
When Creating Your Photo Stream
Step 1: Create a Photo Stream by tapping Photo Stream on your Photos app and tapping the “+” icon at the top left corner of the screen.
Step 2: If you want, add some people that you would like to share your new photo stream with, then name it. On this screen, by toggling the Public Website option ON, you will also be publishing your new photo stream on the web of iCloud.
When It is Already Created
Step 3: If you already created your photo stream and would like to shared it on iCloud’s website for anyone to see, just go to Photos, tap on Photo Stream and then tap on the blue arrow next to the photo stream you created.
Step 4: There turn ON the Public Website toggle.
Step 5: Once you turn ON Public Website sharing for your photo stream, your iPhone or other iOS device will generate a link that you can send to anyone you would like to share your newly created photo stream with.
The person you share your photo stream link with will receive a notification and will be able to access your photo stream from any browser.
There you have it! With this public website feature you will be able to share your photos via Photo Streams even with people who don’t have an iPhone or other iOS device. All they will need to see them is just a web browser and an internet connection.